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Diffstat (limited to 'less.nro')
| -rw-r--r-- | less.nro | 1481 |
1 files changed, 1011 insertions, 470 deletions
@@ -1,26 +1,81 @@ '\" t -.TH LESS 1 "Version 685: 04 Oct 2025" +.TH LESS 1 "10 Jan 2026" "less 691" +.\" Define a string for the caret ("hat") as portably as possible. +.ie \n(.g .ds ^ \(ha +.el .ds ^ ^ +.\" Define a string for the tilde as portably as possible. +.ie \n(.g .ds ~ \(ti +.el .ds ~ ~ +.\" Define a string for the neutral apostrophe as portably as possible. +.ie \n(.g .ds ' \(aq +.el .ds ' ' +.\" Define a string to interpolate the hyphenless break point escape +.\" sequence (for URLs and similar) if the formatter claims groff +.\" compatibility, else interpolate nothing. +.ie \n(.g .ds : \: +.el .ds : \" empty .SH NAME less \- display the contents of a file in a terminal .SH SYNOPSIS +.HP +.nr sA \n(.j \" Save the adjustment mode. +.na +.B less +.\" AT&T man(7) macros accept six arguments at most. +.RB [ \- [ + ] aABcCdeEfFgGiIJKLmMnNqQrRsSuUVwWX\*~\c +] +.RB [ \-b\ \c +.IR size ] +.RB [ \-D\ \c +.IR color ] +.RB [ \-h\ \c +.IR lines ] +.RB [ \-j\ \c +.IR line ] +.RB [ \-k\ \c +.IR key-file ] +.RB [ \- { o | O\c +} +.IR log-file ] +.RB [ \-p\ \c +.I pattern ] +.RB [ \-P\ \c +.IR prompt ] +.RB [ \-t\ \c +.IR tag ] +.RB [ \-T\ \c +.IR tags-file ] +.RB [ \-x\ \c +.IR tab [{\c +.BI , tab\c +}.\|.\|.]]\& +.RB [ \-y\ \c +.IR lines ] +.RB [ \-z\ \c +.IR lines ] +.RB [ \-\c +.IR lines ] +.\" Work around bugs in the man(7) font selection macros in Solaris 10, +.\" Plan 9, and DWB 3.3 troffs. +.\".RB [ "\-\[dq]\c"\" works with groff, mandoc, and Heirloom Doctools +[\fB\-"\c +.IR cc ] +.RB [ \-#\ \c +.IR shift ] +.RB [ +\c +.IR less-command ] +.RB [ \-\- ] +.RI [ file \ .\|.\|.] +.ad \n(sA \" Restore the adjustment mode. +.PP .B "less \-?" .br .B "less \-\-help" -.br +.PP .B "less \-V" .br .B "less \-\-version" -.br -.B "less [\-[+]aABcCdeEfFgGiIJKLmMnNqQrRsSuUVwWX\(ti]" -.br -.B " [\-b \fIspace\/\fP] [\-h \fIlines\/\fP] [\-j \fIline\/\fP] [\-k \fIkeyfile\/\fP]" -.br -.B " [\-{oO} \fIlogfile\/\fP] [\-p \fIpattern\/\fP] [\-P \fIprompt\/\fP] [\-t \fItag\/\fP]" -.br -.B " [\-T \fItagsfile\/\fP] [\-x \fItab\/\fP,...] [\-y \fIlines\/\fP] [\-[z] \fIlines\/\fP]" -.br -.B " [\-# \fIshift\/\fP] [+[+]\fIcmd\/\fP] [\-\-] [\fIfilename\/\fP]..." -.br +.PP (See the OPTIONS section for alternate option syntax with long option names.) . .SH DESCRIPTION @@ -47,35 +102,39 @@ Commands may be preceded by a decimal number, called N in the descriptions below. The number is used by some commands, as indicated. .PP -In the following descriptions, \(haX means control-X. +In the following descriptions, \*^X means control-X. ESC stands for the ESCAPE key; for example ESC-v means the two character sequence "ESCAPE", then "v". .IP "h or H" Help: display a summary of these commands. If you forget all the other commands, remember this one. -.IP "SPACE or \(haV or f or \(haF" -Scroll forward N lines, default one window (see option \-z below). +.IP "SPACE or \*^V or f or \*^F" +Scroll forward N lines, default one window (see option +.B \-z +below). If N is more than the screen size, only the final screenful is displayed. -Warning: some systems use \(haV as a special literalization character. +Warning: some systems use \*^V as a special literalization character. .IP "z" Like SPACE, but if N is specified, it becomes the new window size. -.IP "ENTER or RETURN or \(haN or e or \(haE or j or \(haJ" +.IP "ENTER or RETURN or \*^N or e or \*^E or j or \*^J" Scroll forward N lines, default 1. The entire N lines are displayed, even if N is more than the screen size. -.IP "d or \(haD" +.IP "d or \*^D" Scroll forward N lines, default one half of the screen size. If N is specified, it becomes the new default for subsequent d and u commands. -.IP "b or \(haB or ESC-v" -Scroll backward N lines, default one window (see option \-z below). +.IP "b or \*^B or ESC-v" +Scroll backward N lines, default one window (see option +.B "\-z" +below). If N is more than the screen size, only the final screenful is displayed. .IP "w" Like ESC-v, but if N is specified, it becomes the new window size. -.IP "y or \(haY or \(haP or k or \(haK" +.IP "y or \*^Y or \*^P or k or \*^K" Scroll backward N lines, default 1. The entire N lines are displayed, even if N is more than the screen size. -Warning: some systems use \(haY as a special job control character. -.IP "u or \(haU" +Warning: some systems use \*^Y as a special job control character. +.IP "u or \*^U" Scroll backward N lines, default one half of the screen size. If N is specified, it becomes the new default for subsequent d and u commands. @@ -96,21 +155,33 @@ A file line is a complete line in the file, terminated by a newline. Scroll backwards N file lines, default 1. .IP "ESC-) or RIGHTARROW" Scroll horizontally right N characters, default half the screen width -(see the \-# option). +(see the +.B "\-#" +option). If a number N is specified, it becomes the default for future RIGHTARROW and LEFTARROW commands. -While the text is scrolled, it acts as though the \-S option +While the text is scrolled, it acts as though the +.B "\-S" +option (chop lines) were in effect. .IP "ESC-( or LEFTARROW" Scroll horizontally left N characters, default half the screen width -(see the \-# option). +(see the +.B "\-#" +option). If a number N is specified, it becomes the default for future RIGHTARROW and LEFTARROW commands. -.IP "ESC-} or \(haRIGHTARROW" +.IP "ESC-} or \*^RIGHTARROW or END" Scroll horizontally right to show the end of the longest displayed line. -.IP "ESC-{ or \(haLEFTARROW" +.IP "ESC-{ or \*^LEFTARROW or HOME" Scroll horizontally left back to the first column. -.IP "r or \(haR or \(haL" +.IP "\*^END or SHIFT-END" +Go to line N in the file, default the end of the file, and +scroll horizontally right to show the end of the longest displayed line. +.IP "\*^HOME or SHIFT-HOME" +Go to line N in the file, default 1 (beginning of file), +and scroll horizontally left back to the first column. +.IP "r or \*^R or \*^L" Repaint the screen. .IP R Repaint the screen, discarding any buffered input. @@ -123,14 +194,21 @@ Normally this command would be used when already at the end of the file. It is a way to monitor the tail of a file which is growing while it is being viewed. (The behavior is similar to the "tail \-f" command.) -To stop waiting for more data, enter the interrupt character (usually \(haC). +To stop waiting for more data, enter the interrupt character (usually \*^C). On systems which support .BR poll (2) -you can also use \(haX or the character specified by the \-\-intr option. -If the input is a pipe and the \-\-exit-follow-on-close option is in effect, +you can also use \*^X or the character specified by the +.B "\-\-intr" +option. +If the input is a pipe and the +.B "\-\-exit\-follow\-on\-close" +option is in effect, .B less will automatically stop waiting for data when the input side of the pipe is closed. +.IP "ESC-f" +Like F, but each time a line is found which matches +the last search pattern, the terminal bell is rung. .IP "ESC-F" Like F, but as soon as a line is found which matches the last search pattern, the terminal bell is rung @@ -175,40 +253,44 @@ Like }, but applies to parentheses rather than curly brackets. Like {, but applies to square brackets rather than curly brackets. .IP "]" Like }, but applies to square brackets rather than curly brackets. -.IP "ESC-\(haF" +.IP "ESC-\*^F" Followed by two characters, acts like {, but uses the two characters as open and close brackets, respectively. -For example, "ESC \(haF < >" could be used to +For example, "ESC \*^F < >" could be used to go forward to the > which matches the < in the top displayed line. -.IP "ESC-\(haB" +.IP "ESC-\*^B" Followed by two characters, acts like }, but uses the two characters as open and close brackets, respectively. -For example, "ESC \(haB < >" could be used to +For example, "ESC \*^B < >" could be used to go backward to the < which matches the > in the bottom displayed line. .IP m Followed by any lowercase or uppercase letter, marks the first displayed line with that letter. -If the status column is enabled via the \-J option, +If the status column is enabled via the +.B "\-J" +option, the status column shows the marked line. .IP M Acts like m, except the last displayed line is marked rather than the first displayed line. -.IP "\(aq" +.IP "\*'" (Single quote.) Followed by any lowercase or uppercase letter, returns to the position which was previously marked with that letter. Followed by another single quote, returns to the position at which the last "large" movement command was executed. -Followed by a \(ha or $, jumps to the beginning or end of the +Followed by a \*^ or $, jumps to the beginning or end of the file respectively. Marks are preserved when a new file is examined within a single invocation of .BR less , -so the \(aq command can be used to switch between input files. -The \-\-save-marks option causes marks to be preserved across different invocations of +so the \*' command can be used to switch between input files. +The +.B "\-\-save\-marks" +option causes marks to be preserved across different invocations of .BR less . -.IP "\(haX\(haX" +.IP "\*^X\*^X" Same as single quote. .IP "ESC-m" Followed by any lowercase or uppercase letter, @@ -219,86 +301,104 @@ N defaults to 1. The pattern is a regular expression, as recognized by the regular expression library supplied by your system. By default, searching is case-sensitive (uppercase and lowercase -are considered different); the \-i option can be used to change this. +are considered different); the +.B "\-i" +option can be used to change this. The search starts at the first line displayed -(but see the \-a and \-j options, which change this). -.sp +(but see the +.B "\-a" +and +.B "\-j" +options, which change this). +.IP Certain characters are special if entered at the beginning of the pattern; they modify the type of search rather than become part of the pattern: .RS -.IP "\(haN or !" +.IP "\*^N or !" Search for lines which do NOT match the pattern. -.IP "\(haE or *" +.IP "\*^E or *" Search multiple files. That is, if the search reaches the END of the current file without finding a match, the search continues in the next file in the command line list. -.IP "\(haF or @" +.IP "\*^F or @" Begin the search at the first line of the FIRST file in the command line list, regardless of what is currently displayed on the screen -or the settings of the \-a or \-j options. -.IP "\(haK" +or the settings of the +.B "\-a" +or +.B "\-j" +options. +.IP "\*^K" Highlight any text which matches the pattern on the current screen, but don't move to the first match (KEEP current position). -.IP "\(haR" +.IP "\*^R" Don't interpret regular expression metacharacters; that is, do a simple textual comparison. -.IP "\(haS" +.IP "\*^S" Followed by a digit N between 1 and 5. Only text which has a non-empty match for the N-th parenthesized SUB-PATTERN will be considered to match the pattern. -For example, searching for "(abc)|(def)" modified with \(haS1 +For example, searching for "(abc)|(def)" modified with \*^S1 would search for instances of "abc", but would highlight instances of both "abc" and "def". (Supported only if .B less is built with one of the regular expression libraries .BR posix ", " pcre ", or " pcre2 ".)" -Multiple \(haS modifiers can be specified, +Multiple \*^S modifiers can be specified, to match more than one sub-pattern. -.IP "\(haW" +.IP "\*^W" WRAP around the current file. That is, if the search reaches the end of the current file without finding a match, the search continues from the first line of the current file up to the line where it started. -If the \(haW modifier is set, the \(haE modifier is ignored. -.IP "\(haL" +If the \*^W modifier is set, the \*^E modifier is ignored. +.IP "\*^L" The next character is taken literally; that is, it becomes part of the pattern even if it is one of the above search modifier characters. .RE .IP ?pattern Search backward in the file for the N-th line containing the pattern. The search starts at the last line displayed -(but see the \-a and \-j options, which change this). -.sp +(but see the +.B "\-a" +and +.B "\-j" +options, which change this). +.IP Certain characters are special as in the / command: .RS -.IP "\(haN or !" +.IP "\*^N or !" Search for lines which do NOT match the pattern. -.IP "\(haE or *" +.IP "\*^E or *" Search multiple files. That is, if the search reaches the beginning of the current file without finding a match, the search continues in the previous file in the command line list. -.IP "\(haF or @" +.IP "\*^F or @" Begin the search at the last line of the last file in the command line list, regardless of what is currently displayed on the screen -or the settings of the \-a or \-j options. -.IP "\(haK" +or the settings of the +.B "\-a" +or +.B "\-j" +options. +.IP "\*^K" As in forward searches. -.IP "\(haR" +.IP "\*^R" As in forward searches. -.IP "\(haS" +.IP "\*^S" As in forward searches. -.IP "\(haW" +.IP "\*^W" WRAP around the current file. That is, if the search reaches the beginning of the current file without finding a match, the search continues from the last line of the current file up to the line where it started. -.IP "\(haL" +.IP "\*^L" As in forward searches. .RE .IP "ESC-/pattern" @@ -307,15 +407,15 @@ Same as "/*". Same as "?*". .IP n Repeat previous search, for N-th line containing the last pattern. -If the previous search was modified by \(haN, the search is made for the +If the previous search was modified by \*^N, the search is made for the N-th line NOT containing the pattern. -If the previous search was modified by \(haE, the search continues +If the previous search was modified by \*^E, the search continues in the next (or previous) file if not satisfied in the current file. -If the previous search was modified by \(haR, the search is done +If the previous search was modified by \*^R, the search is done without using regular expressions. -If the previous search was modified by \(haW, the search wraps at +If the previous search was modified by \*^W, the search wraps at the end (or beginning) of the file. -There is no effect if the previous search was modified by \(haF or \(haK. +There is no effect if the previous search was modified by \*^F or \*^K. .IP N Repeat previous search, but in the reverse direction. .IP "ESC-n" @@ -330,11 +430,15 @@ Turn off highlighting of strings matching the current search pattern. If highlighting is already off because of a previous ESC-u command, turn highlighting back on. Any search command will also turn highlighting back on. -(Highlighting can also be disabled by toggling the \-G option; +(Highlighting can also be disabled by toggling the +.B "\-G" +option; in that case search commands do not turn highlighting back on.) .IP "ESC-U" Like ESC-u but also clears the saved search pattern. -If the status column is enabled via the \-J option, +If the status column is enabled via the +.B "\-J" +option, this clears all search matches marked in the status column. .IP "&pattern" Display only lines which match the pattern; @@ -346,12 +450,12 @@ beginning of the prompt, as a reminder that some lines in the file may be hidden. Multiple & commands may be entered, in which case only lines which match all of the patterns will be displayed. -.sp +.IP Certain characters are special as in the / command: .RS -.IP "\(haN or !" +.IP "\*^N or !" Display only lines which do NOT match the pattern. -.IP "\(haR" +.IP "\*^R" Don't interpret regular expression metacharacters; that is, do a simple textual comparison. .RE @@ -373,11 +477,13 @@ If the filename consists of several files, they are all inserted into the list of files and the first one is examined. If the filename contains one or more spaces, the entire filename should be enclosed in double quotes -(also see the \-" option). -.IP "\(haX\(haV or E" +(also see the +.B "\-\[dq]" +option). +.IP "\*^X\*^V or E" Same as :e. -Warning: some systems use \(haV as a special literalization character. -On such systems, you may not be able to use \(haV. +Warning: some systems use \*^V as a special literalization character. +On such systems, you may not be able to use \*^V. .IP ":n" Examine the next file (from the list of files given in the command line). If a number N is specified, the N-th next file is examined. @@ -391,16 +497,18 @@ If a number N is specified, the N-th file in the list is examined. Remove the current file from the list of files. .IP "t" Go to the next tag, if there were more than one matches for the current tag. -See the \-t option for more details about tags. +See the +.B "\-t" +option for more details about tags. .IP "T" Go to the previous tag, if there were more than one matches for the current tag. -.IP "\(haO\(haN or \(haOn" +.IP "\*^O\*^N or \*^On" Search forward in the file for the N-th next OSC 8 hyperlink. -.IP "\(haO\(haP or \(haOp" +.IP "\*^O\*^P or \*^Op" Search backward in the file for the N-th previous OSC 8 hyperlink. -.IP "\(haO\(haL or \(haOl" +.IP "\*^O\*^L or \*^Ol" Jump to the currently selected OSC 8 hyperlink. -.IP "= or \(haG or :f" +.IP "= or \*^G or :f" Prints some information about the file being viewed, including its name and the line number and byte offset of the bottom line being displayed. @@ -411,10 +519,16 @@ and the percent of the file above the last displayed line. Followed by one of the command line option letters (see OPTIONS below), this will change the setting of that option and print a message describing the new setting. -If a \(haP (CONTROL-P) is entered immediately after the dash, +If a \*^P (CONTROL-P) is entered immediately after the dash, the setting of the option is changed but no message is printed. -If the option letter has a numeric value (such as \-b or \-h), -or a string value (such as \-P or \-t), +If the option letter has a numeric value (such as +.B "\-b" +or +.BR "\-h" ")," +or a string value (such as +.B "\-P" +or +.BR "\-t" ")," a new value may be entered after the option letter. If no new value is entered, a message describing the current setting is printed and nothing is changed. @@ -424,14 +538,16 @@ rather than a single option letter. Press ENTER or RETURN after typing the option name to change it. You can enter just the beginning of an option name, then press TAB to find all option names which begin with that string. -A \(haP immediately after the second dash suppresses printing of a +A \*^P immediately after the second dash suppresses printing of a message describing the new setting, as in the \- command. .IP \-+ Followed by one of the command line option letters this will reset the option to its default setting and print a message describing the new setting. (The "\-+\fIX\fP" command does the same thing -as "\-+\fIX\fP" on the command line.) +as +.RB "\[dq]" "\-+X" "\[dq]" +on the command line.) This does not work for string-valued options. .IP \-\-+ Like the \-+ command, but takes a long option name @@ -485,7 +601,7 @@ current file. A pound sign (#) is replaced by the name of the previously examined file. "!!" repeats the last shell command. "!" with no shell command invokes an interactive shell. -If a \(haP (CONTROL-P) is entered immediately after the !, +If a \*^P (CONTROL-P) is entered immediately after the !, no "done" message is printed after the shell command is executed. On Unix systems, the shell is taken from the environment variable SHELL, or defaults to "sh". @@ -501,17 +617,17 @@ The section of the file to be piped is between the position marked by the letter and the current screen. The entire current screen is included, regardless of whether the marked position is before or after the current screen. -<m> may also be \(ha or $ to indicate beginning or end of file respectively. +<m> may also be \*^ or $ to indicate beginning or end of file respectively. If <m> is \&.\& or newline, the current screen is piped. -If a \(haP (CONTROL-P) is entered immediately after the mark letter, +If a \*^P (CONTROL-P) is entered immediately after the mark letter, no "done" message is printed after the shell command is executed. .IP "s filename" Save the input to a file. This works only if the input is a pipe, not an ordinary file. -.IP "\(haO\(haO" +.IP "\*^O\*^O" .RS Run a shell command to open the URI in the current OSC 8 hyperlink, -selected by a previous \(haO\(haN or \(haO\(haP command. +selected by a previous \*^O\*^N or \*^O\*^P command. To find the shell command, the environment variable named "LESS_OSC8_xxx" is read, where "xxx" is the scheme from the URI (the part before the first colon), @@ -527,7 +643,7 @@ There are two special cases: .IP 1. If the URI begins with "#", the remainder of the URI is taken to be the value of the id parameter in another OSC 8 link in the same file, -and \(haO\(haO will simply jump to that link. +and \*^O\*^O will simply jump to that link. .IP 2. If the opener begins with the characters ":e" followed by whitespace and a filename, @@ -538,11 +654,13 @@ the specified filename is opened in the current instance of .PP In a simple case where the opener accepts the complete URI as a command line parameter, the handler may be as simple as +.PP +.EX .nf -.sp -echo mybrowser '%o' -.sp +echo mybrowser \*'%o\*' .fi +.EE +.PP In other cases, the URI may need to be modified, so the handler may have to do some manipulation of the %o value. .PP @@ -557,7 +675,7 @@ which should work on systems which provide the command and a shell with syntax compatible with the Bourne shell .BR sh (1). If you use LESS_OSC8_ANY to override LESS_OSC8_file, you must -set LESS_OSC8_file to "-" to indicate that the default value +set LESS_OSC8_file to "\-" to indicate that the default value should not be used, and likewise for LESS_OSC8_man. .PP The URI passed to an OSC8 handler via %o is guaranteed not to contain any single quote @@ -571,9 +689,9 @@ any metacharacters interpreted by prompt expansion (such as percent, dot, colon, backslash, etc.) must be escaped with a backslash (see the PROMPTS section for details). .RE -.IP "\(haX" +.IP "\*^X" When the "Waiting for data" message is displayed, -such as while in the F command, pressing \(haX +such as while in the F command, pressing \*^X will stop .B less from waiting and return to a prompt. @@ -581,14 +699,16 @@ This may cause .B less to think that the file ends at the current position, so it may be necessary to use the R or F command to see more data. -The \-\-intr option can be used to specify a different character -to use instead of \(haX. +The +.B "\-\-intr" +option can be used to specify a different character +to use instead of \*^X. This command works only on systems that support the .BR poll (2) function. On systems without .BR poll (2), -the interrupt character (usually \(haC) can be used instead. +the interrupt character (usually \*^C) can be used instead. . .SH OPTIONS Command line options are described below. @@ -601,13 +721,30 @@ either a dash followed by a single letter, or two dashes followed by a long option name. A long option name may be abbreviated as long as the abbreviation is unambiguous. -For example, \-\-mouse may be abbreviated \-\-mou, but not -\-\-mo, since both \-\-mouse and \-\-modelines begin with \-\-mo. -Some long option names are in uppercase, such as \-\-QUIT-AT-EOF, as -distinct from \-\-quit-at-eof. +For example, +.B "\-\-mouse" +may be abbreviated +.BR "\-\-mou" "," +but not +.BR "\-\-mo" "," +since both +.B "\-\-mouse" +and +.B "\-\-modelines" +begin with +.BR "\-\-mo" "." + +Some long option names are in uppercase, such as +.BR "\-\-QUIT\-AT\-EOF" "," +as +distinct from +.BR "\-\-quit\-at\-eof" "." Such option names need only have their first letter capitalized; the remainder of the name may be in either case. -For example, \-\-Quit-at-eof is equivalent to \-\-QUIT-AT-EOF. +For example, +.B "\-\-Quit\-at\-eof" +is equivalent to +.BR "\-\-QUIT\-AT\-EOF" "." .PP Options are also taken from the environment variable "LESS". For example, @@ -615,53 +752,70 @@ to avoid typing "less \-options \&...\&" each time .B less is invoked, you might tell .BR csh : -.sp +.PP setenv LESS "\-options" -.sp +.PP or if you use .BR sh : -.sp +.PP LESS="\-options"; export LESS -.sp +.PP On MS-DOS and Windows, you don't need the quotes, but you should be careful that any percent signs in the options string are not interpreted as an environment variable expansion. -.sp +.PP The environment variable is parsed before the command line, so command line options override the LESS environment variable. If an option appears in the LESS variable, it can be reset to its default value on the command line by beginning the command -line option with "\-+". -.sp -Some options like \-k or \-D require a string to follow the option letter. +line option with +.RB "\[dq]" "\-+" "\[dq]." +.PP +Some options like +.B "\-k" +or +.B "\-D" +require a string to follow the option letter. The string for that option is considered to end when a dollar sign ($) is found. -For example, you can set two \-D options like this: -.sp +For example, you can set two +.B "\-D" +options like this: +.PP +.EX LESS="Dnwb$Dsbw" -.sp -If the \-\-use-backslash option appears earlier in the options, then +.EE +.PP +If the +.B "\-\-use\-backslash" +option appears earlier in the options, then a dollar sign or backslash may be included literally in an option string by preceding it with a backslash. -If the \-\-use-backslash option is not in effect, then backslashes are +If the +.B "\-\-use\-backslash" +option is not in effect, then backslashes are not treated specially, and there is no way to include a dollar sign in the option string. -.IP "\-? or \-\-help" +.IP "\fB\-?\fP or \fB\-\-help\fP" This option displays a summary of the commands accepted by .B less (the same as the h command). (Depending on how your shell interprets the question mark, -it may be necessary to quote the question mark, thus: "\-\e?".) -.IP "\-a or \-\-search-skip-screen" +it may be necessary to quote the question mark, thus: "\fB\-\e?\fP".) +.IP "\fB\-a\fP or \fB\-\-search\-skip\-screen\fP" By default, forward searches start at the top of the displayed screen and backwards searches start at the bottom of the displayed screen (except for repeated searches invoked by the n or N commands, which start after or before the "target" line respectively; -see the \-j option for more about the target line). -The \-a option causes forward searches to instead start at +see the +.B "\-j" +option for more about the target line). +The +.B "\-a" +option causes forward searches to instead start at the bottom of the screen and backward searches to start at the top of the screen, thus skipping all lines displayed on the screen. -.IP "\-A or \-\-SEARCH-SKIP-SCREEN" +.IP "\fB\-A\fP or \fB\-\-SEARCH\-SKIP\-SCREEN\fP" Causes all forward searches (not just non-repeated searches) to start just after the target line, and all backward searches to start just before the target line. @@ -670,45 +824,61 @@ Thus, forward searches will skip part of the displayed screen Similarly backwards searches will skip the displayed screen from the last line up to and including the target line. This was the default behavior in less versions prior to 441. -.IP "\-b\fIn\fP or \-\-buffers=\fIn\fP" +.IP "\fB\-b\fP\fIn\fP or \fB\-\-buffers=\fP\fIn\fP" Specifies the amount of buffer space .B less will use for each file, in units of kilobytes (1024 bytes). By default 64\ KB of buffer space is used for each file -(unless the file is a pipe; see the \-B option). -The \-b option specifies instead that \fIn\fP kilobytes of +(unless the file is a pipe; see the +.B "\-B" +option). +The +.B "\-b" +option specifies instead that \fIn\fP kilobytes of buffer space should be used for each file. If \fIn\fP is \-1, buffer space is unlimited; that is, the entire file can be read into memory. -.IP "\-B or \-\-auto-buffers" +.IP "\fB\-B\fP or \fB\-\-auto\-buffers\fP" By default, when data is read from a pipe, buffers are allocated automatically as needed. If a large amount of data is read from the pipe, this can cause a large amount of memory to be allocated. -The \-B option disables this automatic allocation of buffers for pipes, +The +.B "\-B" +option disables this automatic allocation of buffers for pipes, so that only 64\ KB -(or the amount of space specified by the \-b option) +(or the amount of space specified by the +.B "\-b" +option) is used for the pipe. -Warning: use of \-B can result in erroneous display, since only the +Warning: use of +.B "\-B" +can result in erroneous display, since only the most recently viewed part of the piped data is kept in memory; any earlier data is lost. Lost characters are displayed as question marks. -.IP "\-c or \-\-clear-screen" +.IP "\fB\-c\fP or \fB\-\-clear\-screen\fP" Causes full screen repaints to be painted from the top line down. By default, full screen repaints are done by scrolling from the bottom of the screen. -.IP "\-C or \-\-CLEAR-SCREEN" -Same as \-c, for compatibility with older versions of +.IP "\fB\-C\fP or \fB\-\-CLEAR\-SCREEN\fP" +Same as +.BR "\-c" "," +for compatibility with older versions of .BR less . -.IP "\-d or \-\-dumb" -The \-d option suppresses the error message +.IP "\fB\-d\fP or \fB\-\-dumb\fP" +The +.B "\-d" +option suppresses the error message normally displayed if the terminal is dumb; that is, lacks some important capability, such as the ability to clear the screen or scroll backward. -The \-d option does not otherwise change the behavior of +The +.B "\-d" +option does not otherwise change the behavior of .B less on a dumb terminal. -.IP "\-D\fBx\fP\fIcolor\fP or \-\-color=\fBx\fP\fIcolor\fP" +.IP "\fB\-Dx\fP\fIcolor\fP or \fB\-\-color=x\fP\fIcolor\fP" Changes the color of different parts of the displayed text. \fBx\fP is a single character which selects the type of text whose color is being set: @@ -720,11 +890,15 @@ Control characters. .IP "E" Errors and informational messages. .IP "H" -Header lines and columns, set via the \-\-header option. +Header lines and columns, set via the +.B "\-\-header" +option. .IP "M" Mark letters in the status column. .IP "N" -Line numbers enabled via the \-N option. +Line numbers enabled via the +.B "\-N" +option. .IP "P" Prompts. .IP "R" @@ -732,8 +906,10 @@ The rscroll character. .IP "S" Search results. .IP "W" -The highlight enabled via the \-w option. -.IP "1-5" +The highlight enabled via the +.B "\-w" +option. +.IP "1\-5" The text in a search result which matches the first through fifth parenthesized sub-pattern. Sub-pattern coloring works only if @@ -749,25 +925,35 @@ Standout text. .IP "u" Underlined text. .RE - +.PP .RS -The uppercase letters and digits can be used only when the \-\-use-color option is enabled. +The uppercase letters and digits can be used only when the +.B "\-\-use\-color" +option is enabled. When text color is specified by both an uppercase letter and a lowercase letter, the uppercase letter takes precedence. For example, error messages are normally displayed as standout text. So if both "s" and "E" are given a color, the "E" color applies to error messages, and the "s" color applies to other standout text. The lowercase letters refer to bold and underline text formed by -overstriking with backspaces (see the \-U option) and to non-content +overstriking with backspaces (see the +.B "\-U" +option) and to non-content text (such as line numbers and prompts), -but not to text formatted using ANSI escape sequences with the \-R option +but not to text formatted using ANSI escape sequences with the +.B "\-R" +option (but see the note below for different behavior on Windows and MS-DOS). .PP A lowercase letter may be followed by a + to indicate that the normal format change and the specified color should both be used. -For example, \-Dug displays underlined text as green without underlining; +For example, +.B "\-Dug" +displays underlined text as green without underlining; the green color has replaced the usual underline formatting. -But \-Du+g displays underlined text as both green and in underlined format. +But +.B "\-Du+g" +displays underlined text as both green and in underlined format. .PP \fIcolor\fP is either a 4-bit color string or an 8-bit color string: .PP @@ -792,10 +978,14 @@ White Yellow .PP The corresponding uppercase letter denotes a brighter shade of the color. -For example, \-DNGk displays line numbers as bright green text on a black -background, and \-DEbR displays error messages as blue text on a +For example, +.B "\-DNGk" +displays line numbers as bright green text on a black +background, and +.B "\-DEbR" +displays error messages as blue text on a bright red background. -If either character is a "-" or is omitted, the corresponding color +If either character is a "\-" or is omitted, the corresponding color is set to that of normal text. .PP An 8-bit color string is one or two decimal integers separated by a dot, @@ -804,9 +994,9 @@ the second specifies the background color. Each integer is a value between 0 and 255 inclusive which selects a "CSI 38;5" color value (see .nh -https://en.wikipedia.org/wiki/ANSI_escape_code#SGR). +https://\*:en\*:.wikipedia\*:.org/\*:wiki/\*:ANSI_escape_code\*:#SGR). .hy -If either integer is a "-" or is omitted, +If either integer is a "\-" or is omitted, the corresponding color is set to that of normal text. .PP A 4-bit or 8-bit color string may be followed by one or more of the @@ -820,15 +1010,19 @@ Bold .IP "l or &" Blinking .PP -On MS-DOS and Windows, the \-\-color option behaves +On MS-DOS and Windows, the +.B "\-\-color" +option behaves differently from what is described above in these ways: .IP \(bu The bold (d and *) and blinking (l and &) text attributes at the end of a color string are not supported. .IP \(bu Lowercase color selector letters refer to text formatted by ANSI -escape sequences with \-R, -in addition to overstruck and non-content text (but see \-Da). +escape sequences with +.BR "\-R" "," +in addition to overstruck and non-content text (but see +.BR "\-Da" ")." .IP \(bu For historical reasons, when a lowercase color selector letter is followed by a numeric color value, @@ -840,9 +1034,9 @@ CHAR_INFO.Attributes value, between 0 and 15 inclusive (see .nh -https://learn.microsoft.com/en-us/windows/console/char-info-str). +https://\*:learn\*:.microsoft\*:.com/\*:en\-us/\*:windows/\*:console/\*:char\-info\-str). .hy - +.IP To avoid confusion, it is recommended that the equivalent letters rather than numbers be used after a lowercase color selector on MS-DOS/Windows. .IP \(bu @@ -852,15 +1046,19 @@ are not supported on systems earlier than Windows 10. Only a limited set of ANSI escape sequences to set color in the content work correctly. 4-bit color sequences work, but "CSI 38;5" color sequences do not. .IP \(bu -The \-Da option makes the behavior of \-\-color +The +.B "\-Da" +option makes the behavior of +.B "\-\-color" more similar to its behavior on non-MS-DOS/Windows systems by (1) making lowercase color selector letters not affect text formatted with ANSI escape sequences, and (2) allowing "CSI 38;5" color sequences in the content work by passing them to the terminal (only on Windows 10 and later; on -earlier Windows systems, such sequences do not work regardless of the setting of \-Da). +earlier Windows systems, such sequences do not work regardless of the setting of +.BR "\-Da" ")." .RE -.IP "\-e or \-\-quit-at-eof" +.IP "\fB\-e\fP or \fB\-\-quit\-at\-eof\fP" Causes .B less to automatically exit @@ -868,11 +1066,11 @@ the second time it reaches end-of-file. By default, the only way to exit .B less is via the "q" command. -.IP "\-E or \-\-QUIT-AT-EOF" +.IP "\fB\-E\fP or \fB\-\-QUIT\-AT\-EOF\fP" Causes .B less to automatically exit the first time it reaches end-of-file. -.IP "\-f or \-\-force" +.IP "\fB\-f\fP or \fB\-\-force\fP" Forces non-regular files to be opened. (A non-regular file is a directory or a device special file.) Also suppresses the warning message when a binary file is opened. @@ -880,41 +1078,49 @@ By default, .B less will refuse to open non-regular files. Note that some operating systems will not allow directories -to be read, even if \-f is set. -.IP "\-F or \-\-quit-if-one-screen" +to be read, even if +.B "\-f" +is set. +.IP "\fB\-F\fP or \fB\-\-quit\-if\-one\-screen\fP" Causes .B less to automatically exit if the entire file can be displayed on the first screen. Also see the description of the LESS_SHELL_LINES environment variable below. -.IP "\-g or \-\-hilite-search" +.IP "\fB\-g\fP or \fB\-\-hilite\-search\fP" Normally, .B less will highlight ALL strings which match the last search command. -The \-g option changes this behavior to highlight only the particular string +The +.B "\-g" +option changes this behavior to highlight only the particular string which was found by the last search command. This can cause .B less to run somewhat faster than the default. -.IP "\-G or \-\-HILITE-SEARCH" +.IP "\fB\-G\fP or \fB\-\-HILITE\-SEARCH\fP" The \-G option suppresses all highlighting of strings found by search commands. -.IP "\-h\fIn\fP or \-\-max-back-scroll=\fIn\fP" +.IP "\fB\-h\fP\fIn\fP or \fB\-\-max\-back\-scroll=\fP\fIn\fP" Specifies a maximum number of lines to scroll backward. If it is necessary to scroll backward more than \fIn\fP lines, the screen is repainted in a forward direction instead. (If the terminal does not have the ability to scroll -backward, \-h0 is implied.) -.IP "\-i or \-\-ignore-case" +backward, +.B "\-h0" +is implied.) +.IP "\fB\-i\fP or \fB\-\-ignore\-case\fP" Causes searches to ignore case; that is, uppercase and lowercase are considered identical. This option is ignored if any uppercase letters appear in the search pattern; in other words, if a pattern contains uppercase letters, then that search does not ignore case. -.IP "\-I or \-\-IGNORE-CASE" -Like \-i, but searches ignore case even if +.IP "\fB\-I\fP or \fB\-\-IGNORE\-CASE\fP" +Like +.BR "\-i" "," +but searches ignore case even if the pattern contains uppercase letters. -.IP "\-j\fIn\fP or \-\-jump-target=\fIn\fP" +.IP "\fB\-j\fP\fIn\fP or \fB\-\-jump\-target=\fP\fIn\fP" Specifies a line on the screen where the "target" line is to be positioned. The target line is the line specified by any command to @@ -930,28 +1136,40 @@ of the screen, starting with a decimal point: \&.5 is in the middle of the screen, \&.3 is three tenths down from the first line, and so on. If the line is specified as a fraction, the actual line number is recalculated if the terminal window is resized. -If the \-\-header option is used and the target line specified by \-j +If the +.B "\-\-header" +option is used and the target line specified by +.B "\-j" would be obscured by the header, the target line is moved to the first line after the header. .RS .PP -If any form of the \-j option is used, +If any form of the +.B "\-j" +option is used, repeated forward searches (invoked with "n" or "N") begin at the line immediately after the target line, and repeated backward searches begin at the target line, -unless changed by \-a or \-A. -For example, if "\-j4" is used, the target line is the +unless changed by +.B "\-a" +or +.BR "\-A" "." +For example, if +.RB "\[dq]" "\-j4" "\[dq]" +is used, the target line is the fourth line on the screen, so forward searches begin at the fifth line on the screen. However nonrepeated searches (invoked with "/" or "?") -always begin at the start or end of the current screen respectively. +always begin at the first or last line on the screen respectively. .RE -.IP "\-J or \-\-status-column" +.IP "\fB\-J\fP or \fB\-\-status\-column\fP" Displays a status column at the left edge of the screen. The character displayed in the status column may be one of: .RS .IP ">" -The line is chopped with the \-S option, and +The line is chopped with the +.B "\-S" +option, and the text that is chopped off beyond the right edge of the screen contains a match for the current search. .IP "<" @@ -966,21 +1184,30 @@ There are matches in the visible part of the line but none to the right or left of it. .IP "a-z, A-Z" The line has been marked with the corresponding letter via the m or M command. +.IP "#" +The line has been marked by left-clicking it with the mouse +when the +.B "\-\-mouse" +option is in effect. .RE -.IP "\-k\fIfilename\fP or \-\-lesskey-file=\fIfilename\fP" +.IP "\fB\-k\fP\fIfilename\fP or \fB\-\-lesskey\-file=\fP\fIfilename\fP" Causes .B less to open and interpret the named file as a .BR lesskey (1) binary file. -Multiple \-k options may be specified. +Multiple +.B "\-k" +options may be specified. If the LESSKEY or LESSKEY_SYSTEM environment variable is set, or if a lesskey file is found in a standard place (see KEY BINDINGS), it is also used as a .B lesskey file. -Note the warning under "\-\-lesskey-content" below. -.IP "\-\-lesskey-src=\fIfilename\fP" +Note the warning under +.B "\-\-lesskey\-content" +below. +.IP "\fB\-\-lesskey\-src=\fP\fIfilename\fP" Causes .B less to open and interpret the named file as a @@ -1002,8 +1229,10 @@ Newer versions of .B less read the lesskey source file directly and ignore the binary file if the source file exists. -Note the warning under "\-\-lesskey-content" below. -.IP "\-\-lesskey-content=\fItext\fP" +Note the warning under +.B "\-\-lesskey\-content" +below. +.IP "\fB\-\-lesskey\-content=\fP\fItext\fP" Causes .B less to interpret the specified text as the contents of a @@ -1013,35 +1242,34 @@ In the text, .B lesskey lines may be separated by either newlines as usual, or by semicolons. A literal semicolon may be represented by a backslash followed by a semicolon. -.sp +.IP Warning: certain environment variables such as LESS, LESSSECURE, LESSCHARSET and others, which are used early in startup, cannot be set in a file specified by a command line option -(\-\-lesskey, \-\-lesskey-src or \-\-lesskey-content). When using a +.RB "(" "\-\-lesskey" "," "\-\-lesskey\-src" " or " "\-\-lesskey\-content" ")." +When using a .B lesskey file to set environment variables, it is safer to use the default lesskey file, or to specify the file using the LESSKEYIN or LESSKEY_CONTENT environment variables rather than using a command line option. -.IP "\-K or \-\-quit-on-intr" +.IP "\fB\-K\fP or \fB\-\-quit\-on\-intr\fP" Causes .B less to exit immediately (with status 2) -when an interrupt character (usually \(haC) is typed. +when an interrupt character (usually \*^C) is typed. Normally, an interrupt character causes .B less to stop whatever it is doing and return to its command prompt. -Note that use of this option makes it impossible to return to the -command prompt from the "F" command. -.IP "\-L or \-\-no-lessopen" +.IP "\fB\-L\fP or \fB\-\-no\-lessopen\fP" Ignore the LESSOPEN environment variable (see the INPUT PREPROCESSOR section below). This option can be set from within .BR less , but it will apply only to files opened subsequently, not to the file which is currently open. -.IP "\-m or \-\-long-prompt" +.IP "\fB\-m\fP or \fB\-\-long\-prompt\fP" Causes .B less to prompt verbosely (like @@ -1050,12 +1278,12 @@ with the percent into the file. By default, .B less prompts with a colon. -.IP "\-M or \-\-LONG-PROMPT" +.IP "\fB\-M\fP or \fB\-\-LONG\-PROMPT\fP" Causes .B less to prompt even more verbosely than .BR more (1). -.IP "\-n or \-\-line-numbers" +.IP "\fB\-n\fP or \fB\-\-line\-numbers\fP" Suppresses line numbers. The default (to use line numbers) may cause .B less @@ -1064,10 +1292,10 @@ Using line numbers means: the line number will be displayed in the verbose prompt and in the = command, and the v command will pass the current line number to the editor (see also the discussion of LESSEDIT in PROMPTS below). -.IP "\-N or \-\-LINE-NUMBERS" +.IP "\fB\-N\fP or \fB\-\-LINE\-NUMBERS\fP" Causes a line number to be displayed at the beginning of each line in the display. -.IP "\-o\fIfilename\fP or \-\-log-file=\fIfilename\fP" +.IP "\fB\-o\fP\fIfilename\fP or \fB\-\-log\-file=\fP\fIfilename\fP" Causes .B less to copy its input to the named file as it is being viewed. @@ -1076,24 +1304,34 @@ not an ordinary file. If the file already exists, .B less will ask for confirmation before overwriting it. -.IP "\-O\fIfilename\fP or \-\-LOG-FILE=\fIfilename\fP" -The \-O option is like \-o, but it will overwrite an existing +.IP "\fB\-O\fP\fIfilename\fP or \fB\-\-LOG\-FILE=\fP\fIfilename\fP" +The +.B "\-O" +option is like +.B "\-o," +but it will overwrite an existing file without asking for confirmation. -.sp +.IP If no log file has been specified, -the \-o and \-O options can be used from within +the +.B "\-o" +and +.B "\-O" +options can be used from within .B less to specify a log file. Without a file name, they will simply report the name of the log file. -The "s" command is equivalent to specifying \-o from within +The "s" command is equivalent to specifying +.B "\-o" +from within .BR less . -.IP "\-p\fIpattern\fP or \-\-pattern=\fIpattern\fP" +.IP "\fB\-p\fP\fIpattern\fP or \fB\-\-pattern=\fP\fIpattern\fP" The \-p option on the command line is equivalent to specifying +/\fIpattern\fP; that is, it tells .B less to start at the first occurrence of \fIpattern\fP in the file. -.IP "\-P\fIprompt\fP or \-\-prompt=\fIprompt\fP" +.IP "\fB\-P\fP\fIprompt\fP or \fB\-\-prompt=\fP\fIprompt\fP" Provides a way to tailor the three prompt styles to your own preference. This option would normally be put in the LESS environment @@ -1102,18 +1340,37 @@ variable, rather than being typed in with each command. Such an option must either be the last option in the LESS variable, or be terminated by a dollar sign. - \-Ps followed by a string changes the default (short) prompt +.PP +.RS +.TP +\fB\-Ps\fP +followed by a string changes the default (short) prompt to that string. - \-Pm changes the medium (\-m) prompt. - \-PM changes the long (\-M) prompt. - \-Ph changes the prompt for the help screen. - \-P= changes the message printed by the = command. - \-Pw changes the message printed while waiting for data (in the "F" command). -.sp 1 +.TP +\fB\-Pm\fP +changes the medium +.RB "(" "\-m" ")" +prompt. +.TP +\fB\-PM\fP +changes the long +.RB "(" "\-M" ")" +prompt. +.TP +\fB\-Ph\fP +changes the prompt for the help screen. +.TP +\fB\-P=\fP +changes the message printed by the = command. +.TP +\fB\-Pw\fP +changes the message printed while waiting for data (in the "F" command). +.RE +.IP All prompt strings consist of a sequence of letters and special escape sequences. See the section on PROMPTS for more details. -.IP "\-q or \-\-quiet or \-\-silent" +.IP "\fB\-q\fP or \fB\-\-quiet\fP or \fB\-\-silent\fP" Causes moderately "quiet" operation: the terminal bell is not rung if an attempt is made to scroll past the end of the file @@ -1122,56 +1379,73 @@ If the terminal has a "visual bell", it is used instead. The bell will be rung on certain other errors, such as typing an invalid character. The default is to ring the terminal bell in all such cases. -.IP "\-Q or \-\-QUIET or \-\-SILENT" +.IP "\fB\-Q\fP or \fB\-\-QUIET\fP or \fB\-\-SILENT\fP" Causes totally "quiet" operation: the terminal bell is never rung. If the terminal has a "visual bell", it is used in all cases where the terminal bell would have been rung. -.IP "\-r or \-\-raw-control-chars" +.IP "\fB\-r\fP or \fB\-\-raw\-control\-chars\fP" Causes "raw" control characters to be displayed. The default is to display control characters using the caret notation; -for example, a control-A (octal 001) is displayed as "\(haA" -(with some exceptions as described under the \-U option). -Warning: when the \-r option is used, +for example, a control-A (octal 001) is displayed as "\*^A" +(with some exceptions as described under the +.B "\-U" +option). +Warning: when the +.B "\-r" +option is used, .B less cannot keep track of the actual appearance of the screen (since this depends on how the screen responds to each type of control character). Thus, various display problems may result, such as long lines being split in the wrong place. -.sp -USE OF THE \-r OPTION IS DANGEROUS AND IS NOT RECOMMENDED. +.IP +USE OF THE +.B "\-r" +OPTION IS DANGEROUS AND IS NOT RECOMMENDED. .br -The \-r option can be set on the command line or via the \- command, +The +.B "\-r" +option can be set on the command line or via the \- command, but to avoid unintentional use, it cannot be set in a LESS environment variable. -If \-r appears in a LESS environment variable, it is treated as if it were \-R. -.IP "\-R or \-\-RAW-CONTROL-CHARS" -Like \-r, but only a limited set of escape +If +.B "\-r" +appears in a LESS environment variable, it is treated as if it were +.BR "\-R" "." +.IP "\fB\-R\fP or \fB\-\-RAW\-CONTROL\-CHARS\fP" +Like +.BR "\-r" "," +but only a limited set of escape sequences are output in "raw" form. -Unlike \-r, the screen appearance is maintained correctly. +Unlike +.BR "\-r" "," +the screen appearance is maintained correctly. The sequences which are output raw are: -.sp +.IP 1. ANSI SGR ("color") sequences -.sp +.IP 2. OSC 8 hyperlinks -.sp +.IP 3. Other OSC sequences, if the OSC type number is listed in the LESSANSIOSCALLOW environment variable -.sp +.IP 4. OSC sequences starting with a non-standard introductory character (that is, something other than "]"), if the character is listed in the LESSANSIOSCCHARS environment variable followed by an asterisk -.sp +.IP ANSI color escape sequences are sequences of the form: -.sp +.IP +.EX ESC [ \&...\& m -.sp +.EE +.IP where the "...\&" is zero or more color specification characters. Color escape sequences are only supported when the color is changed within one line, not across lines. In other words, the beginning of each line is assumed to be normal (non-colored), regardless of any escape sequences in previous lines. -.sp +.IP You can make .B less think that characters other than "m" can end ANSI color escape sequences @@ -1182,31 +1456,41 @@ And you can make think that characters other than the standard ones may appear between the ESC and the m by setting the environment variable LESSANSIMIDCHARS to the list of characters which can appear. -.sp +.IP OSC sequences are of the form: -.sp - ESC ] N ; \&...\& \\7 -.sp +.IP +.EX + ESC ] N ; \&...\& \e7 +.EE +.IP where the OSC type number N is a decimal integer. -The terminating sequence may be either a BEL character (\\7) -as above, or the two-character sequence "ESC \\". -.IP "\-s or \-\-squeeze-blank-lines" +The terminating sequence may be either a BEL character (\e7) +as above, or the two-character sequence "ESC \e". +.IP "\fB\-s\fP or \fB\-\-squeeze\-blank\-lines\fP" Causes consecutive blank lines to be squeezed into a single blank line. This is useful when viewing .BR nroff (1) output. -.IP "\-S or \-\-chop-long-lines" +.IP "\fB\-S\fP or \fB\-\-chop\-long\-lines\fP" Causes lines longer than the screen width to be chopped (truncated) rather than wrapped. That is, the portion of a long line that does not fit in the screen width is not displayed until you press RIGHT-ARROW. The default is to wrap long lines; that is, display the remainder on the next line. -See also the \-\-wordwrap option. -While the \-\-header option is active, the \-S option is ignored, +See also the +.B "\-\-wordwrap" +option. +While the +.B "\-\-header" +option is active, the +.B "\-S" +option is ignored, and lines longer than the screen width are truncated. -.IP "\-t\fItag\fP or \-\-tag=\fItag\fP" -The \-t option, followed immediately by a TAG, +.IP "\fB\-t\fP\fItag\fP or \fB\-\-tag=\fP\fItag\fP" +The +.B "\-t" +option, followed immediately by a TAG, will edit the file containing that tag. For this to work, tag information must be available; for example, there may be a file in the current directory called "tags", @@ -1219,24 +1503,34 @@ the name of a command compatible with and that command is executed to find the tag. (See .nh -http://www.gnu.org/software/global/global.html). +http://\*:www\*:.gnu\*:.org/\*:software/\*:global/\*:global\*:.html). .hy -The \-t option may also be specified from within +The +.B "\-t" +option may also be specified from within .B less (using the \- command) as a way of examining a new file. -The command ":t" is equivalent to specifying \-t from within +The command ":t" is equivalent to specifying +.B "\-t" +from within .BR less . -.IP "\-T\fItagsfile\fP or \-\-tag-file=\fItagsfile\fP" +.IP "\fB\-T\fP\fItagsfile\fP or \fB\-\-tag\-file=\fP\fItagsfile\fP" Specifies a tags file to be used instead of "tags". -.IP "\-u or \-\-underline-special" +.IP "\fB\-u\fP or \fB\-\-underline\-special\fP" Causes backspaces and carriage returns to be treated as printable characters; that is, they are sent to the terminal when they appear in the input. -.IP "\-U or \-\-UNDERLINE-SPECIAL" +.IP "\fB\-U\fP or \fB\-\-UNDERLINE\-SPECIAL\fP" Causes backspaces, tabs, carriage returns and "formatting characters" (as defined by Unicode) to be treated as control characters; -that is, they are handled as specified by the \-r option. -.sp -By default, if neither \-u nor \-U is given, +that is, they are handled as specified by the +.B "\-r" +option. +.IP +By default, if neither +.B "\-u" +nor +.B "\-U" +is given, backspaces which appear adjacent to an underscore character are treated specially: the underlined text is displayed @@ -1247,53 +1541,76 @@ the overstruck text is printed using the terminal's hardware boldface capability. Other backspaces are deleted, along with the preceding character. Carriage returns immediately followed by a newline are deleted. -Other carriage returns are handled as specified by the \-r option. +Other carriage returns are handled as specified by the +.B "\-r" +option. Unicode formatting characters, such as the Byte Order Mark, are sent to the terminal. Text which is overstruck or underlined can be searched for -if neither \-u nor \-U is in effect. -.sp -See also the \-\-proc-backspace, \-\-proc-tab, -and \-\-proc-return options. -.IP "\-V or \-\-version" +if neither +.B "\-u" +nor +.B "\-U" +is in effect. +.IP +See also the +.BR "\-\-proc\-backspace" "," "\-\-proc\-tab" ", and " "\-\-proc\-return" +options. +.IP "\fB\-V\fP or \fB\-\-version\fP" Displays the version number of .BR less . -.IP "\-w or \-\-hilite-unread" +.IP "\fB\-w\fP or \fB\-\-hilite\-unread\fP" Temporarily highlights the first "new" line after a forward movement of a full page. The first "new" line is the line immediately following the line previously at the bottom of the screen. Also highlights the target line after a g or p command. The highlight is removed at the next command which causes movement. -If the \-\-status-line option is in effect, the entire line +If the +.B "\-\-status\-line" +option is in effect, the entire line (the width of the screen) is highlighted. Otherwise, only the text in the line is highlighted, -unless the \-J option is in effect, +unless the +.B "\-J" +option is in effect, in which case only the status column is highlighted. -.IP "\-W or \-\-HILITE-UNREAD" -Like \-w, but temporarily highlights the first new line after any +.IP "\fB\-W\fP or \fB\-\-HILITE\-UNREAD\fP" +Like +.BR "\-w" "," +but temporarily highlights the first new line after any forward movement command larger than one line. -.IP "\-x\fIn\fP,...\& or \-\-tabs=\fIn\fP,..." +.IP "\fB\-x\fP\fIn\fP,...\& or \fB\-\-tabs=\fP\fIn\fP,..." Sets tab stops. If only one \fIn\fP is specified, tab stops are set at multiples of \fIn\fP. If multiple values separated by commas are specified, tab stops are set at those positions, and then continue with the same spacing as the last two. -For example, "-x9,17" will set tabs at positions 9, 17, 25, 33, etc. +For example, +.RB "\[dq]" "\-x9,17" "\[dq]" +will set tabs at positions 9, 17, 25, 33, etc. The default for \fIn\fP is 8. -.IP "\-X or \-\-no-init" +.IP "\fB\-X\fP or \fB\-\-no\-init\fP" Disables sending the termcap initialization and deinitialization strings to the terminal. -This is sometimes desirable if the deinitialization string does +This is sometimes desirable if initialization or deinitialization does something unnecessary, like clearing the screen. -.IP "\-y\fIn\fP or \-\-max-forw-scroll=\fIn\fP" +Note that some terminals require the initialization string for proper +operation, so they may not behave completely correctly when +.B "\-X" +is used. +.IP "\fB\-y\fP\fIn\fP or \fB\-\-max\-forw\-scroll=\fP\fIn\fP" Specifies a maximum number of lines to scroll forward. If it is necessary to scroll forward more than \fIn\fP lines, the screen is repainted instead. -The \-c or \-C option may be used to repaint from the top of +The +.B "\-c" +or +.B "\-C" +option may be used to repaint from the top of the screen if desired. By default, any forward movement causes scrolling. -.IP "\-z\fIn\fP or \-\-window=\fIn\fP or \-\fIn\fP" +.IP "\fB\-z\fP\fIn\fP or \fB\-\-window=\fP\fIn\fP or \-\fIn\fP" Changes the default scrolling window size to \fIn\fP lines. The default is one screenful. The z and w commands can also be used to change the window size. @@ -1304,10 +1621,12 @@ If the number is negative, it indicates .I n lines less than the current screen size. -For example, if the screen is 24 lines, \fI\-z\-4\fP sets the +For example, if the screen is 24 lines, +.B "\-z\-4" +sets the scrolling window to 20 lines. If the screen is resized to 40 lines, the scrolling window automatically changes to 36 lines. -.IP "\-\(dq\fIcc\fP\ or\ \-\-quotes=\fIcc\fP" +.IP "\fB\-""\fP\fIcc\fP\ or\ \fB\-\-quotes=\fP\fIcc\fP" Changes the filename quoting character. This may be necessary if you are trying to name a file which contains both spaces and quote characters. @@ -1321,10 +1640,10 @@ Filenames containing a space should then be preceded by the open quote character and followed by the close quote character. Note that even after the quote characters are changed, this option remains \-" (a dash followed by a double quote). -.IP "\-\(ti or \-\-tilde" -Normally lines after end of file are displayed as a single tilde (\(ti). +.IP "\fB\-\*~\fP or \fB\-\-tilde\fP" +Normally lines after end of file are displayed as a single tilde (\*~). This option causes lines after end of file to be displayed as blank lines. -.IP "\-# or \-\-shift" +.IP "\fB\-#\fP or \fB\-\-shift\fP" Specifies the default number of positions to scroll horizontally in the RIGHTARROW and LEFTARROW commands. If the number specified is zero, it sets the default number of @@ -1334,35 +1653,69 @@ of the screen, starting with a decimal point: \&.5 is half of the screen width, \&.3 is three tenths of the screen width, and so on. If the number is specified as a fraction, the actual number of scroll positions is recalculated if the terminal window is resized. -.IP "\-\-cmd=\fIcommands\fP +.IP "\fB\-\-autosave=\fP\fIactions\fP +Normally the history file is saved only when +.B less +exits. +This option specifies other actions which will cause the history file to be saved. +Each action is defined by a single character in the \fIactions\fP string: +.RS +.IP "m" +Setting or clearing a mark while +.B "\-\-save-marks" +is in effect. +.IP "/" +Searching. +.IP "!" +Running a shell command. +.IP "*" +Any action; same as "m/!". +.RE +.IP +Can be set to "-" to specify the default, that only exiting +.B less +will cause the history file to be saved. +Note that, depending on your shell, if you specify this option on the +command line, the "!" and "*" characters may need to be escaped or quoted. +.IP "\fB\-\-cmd=\fP\fIcommands\fP The specified string is taken to be an initial command to .BR less . This is similar to specifying "+\fIcommands\fP", except that -commands specified by \-\-cmd are not executed if +commands specified by +.B "\-\-cmd" +are not executed if .B less -exits immediately due to the use of the \-E or \-F option, while +exits immediately due to the use of the +.B "\-E" +or +.B "\-F" +option, while commands specified by the \fB+\fP option are executed even if .B less exits immediately. -.IP "\-\-exit-follow-on-close" +.IP "\fB\-\-exit\-follow\-on\-close\fP" When using the "F" command on a pipe, .B less will automatically stop waiting for more data when the input side of the pipe is closed. -.IP "\-\-file-size" -If \-\-file-size is specified, +.IP "\fB\-\-file\-size\fP" +If +.B "\-\-file\-size" +is specified, .B less will determine the size of the file immediately after opening the file. Then the "=" command will display the number of lines in the file. Normally this is not done, because it can be slow if the input file is non-seekable (such as a pipe) and is large. -.IP "\-\-follow-name" +.IP "\fB\-\-follow\-name\fP" Normally, if the input file is renamed while an F command is executing, .B less will continue to display the contents of the original file despite its name change. -If \-\-follow-name is specified, during an F command +If +.B "\-\-follow\-name" +is specified, during an F command .B less will periodically attempt to reopen the file by name. If the reopen succeeds and the file is a different file from the original @@ -1370,11 +1723,11 @@ If the reopen succeeds and the file is a different file from the original with the same name as the original (now renamed) file), .B less will display the contents of that new file. -.IP "\-\-form-feed" +.IP "\fB\-\-form\-feed\fP" When scrolling forward or backward in the file, -stop if a line beginning with a form feed character (\(haL) is reached. +stop if a line beginning with a form feed character (\*^L) is reached. This can be useful when viewing a file which uses form feeds between pages. -.IP "\-\-header=\fIL\fP,\fIC\fP,\fIN\fP" +.IP "\fB\-\-header=\fP\fIL\fP,\fIC\fP,\fIN\fP" .RS Sets the number of header lines and columns displayed on the screen. The number of header lines is set to \fIL\fP. @@ -1386,11 +1739,18 @@ If \fIC\fP is empty or missing, the number of header columns is unchanged. The first header line is set to line number \fIN\fP in the file. If \fIN\fP is empty or missing, it is taken to be the number of the line currently displayed in the first line of the screen -(if the \-\-header command has been issued from within +(if the +.B "\-\-header" +command has been issued from within .BR less ")," -or 1 (if the \-\-header option has been given on the command line). -The special form "\-\-header=\-" disables header lines and header columns, -and is equivalent to "\-\-header=0,0". +or 1 (if the +.B "\-\-header" +option has been given on the command line). +The special form +.RB "\[dq]" "\-\-header=\-" "\[dq]" +disables header lines and header columns, +and is equivalent to +.RB "\[dq]" "\-\-header=0,0" "\[dq]." .PP When \fIL\fP is nonzero, the first \fIL\fP lines at the top of the screen are replaced with the \fIL\fP lines of the file beginning at line \fIN\fP, @@ -1400,28 +1760,34 @@ When \fIC\fP is nonzero, the first \fIC\fP characters displayed at the beginning of each line are replaced with the first \fIC\fP characters of the line, even if the rest of the line is scrolled horizontally. .PP -While the \-\-header option is active, +While the +.B "\-\-header" +option is active, lines longer than the screen width are truncated, -and the \-S option is ignored. +and the +.B "\-S" +option is ignored. .RE -.IP "\-\-incsearch" +.IP "\fB\-\-incsearch\fP" Subsequent search commands will be "incremental"; that is, .B less will advance to the next line containing the search pattern as each character of the pattern is typed in. -.IP "\-\-intr=\fIc\fP" -Use the character \fIc\fP instead of \(haX to interrupt a read +.IP "\fB\-\-intr=\fP\fIc\fP" +Use the character \fIc\fP instead of \*^X to interrupt a read when the "Waiting for data" message is displayed. \fIc\fP must be an ASCII character; that is, one with a value between 1 and 127 inclusive. A caret followed by a single character can be used to specify a control character. -.IP "\-\-line-num-width=\fIn\fP" +.IP "\fB\-\-line\-num\-width=\fP\fIn\fP" Sets the minimum width of the line number field when the \-N option is in effect to \fIn\fP characters. The default is 7. -.IP "\-\-match-shift=\fIn\fP" -When \-S is in effect, if a search match is not visible +.IP "\fB\-\-match\-shift=\fP\fIn\fP" +When +.B "\-S" +is in effect, if a search match is not visible because it is shifted to the left or right of the currently visible screen, the text will horizontally shift to ensure that the search match is visible. @@ -1429,13 +1795,13 @@ This option selects the column in which the first character of the search match will be placed after the shift. In other words, there will be \fIn\fP characters visible to the left of the search match. - +.IP Alternately, the number may be specified as a fraction of the width of the screen, starting with a decimal point: \&.5 is half of the screen width, \&.3 is three tenths of the screen width, and so on. If the number is specified as a fraction, the actual number of scroll positions is recalculated if the terminal window is resized. -.IP "\-\-modelines=\fIn\fP" +.IP "\fB\-\-modelines=\fP\fIn\fP" .RS Before displaying a file, .B less @@ -1459,10 +1825,14 @@ option settings may be separated by either spaces or colons. The word "set" is required if the program name is "less" but optional if any of the other three names are used. If any option setting is of the form "tabstop=\fIn\fP" or "ts=\fIn\fP", -then tab stops are automatically set as if \-\-tabs=\fIn\fP had been given. -See the \-\-tabs description for acceptable values of \fIn\fP. +then tab stops are automatically set as if +.BI "\-\-tabs=" "n" +had been given. +See the +.B "\-\-tabs" +description for acceptable values of \fIn\fP. .RE -.IP "\-\-mouse" +.IP "\fB\-\-mouse\fP" Enables mouse input: scrolling the mouse wheel down moves forward in the file, scrolling the mouse wheel up moves backwards in the file, @@ -1470,83 +1840,125 @@ left-click sets the "#" mark to the line where the mouse is clicked, and right-click (or any other) returns to the "#" mark position. Holding down the left button and dragging also moves in the file. If a left-click is performed with the mouse cursor on an OSC 8 hyperlink, -the hyperlink is selected as if by the \(haO\(haN command. +the hyperlink is selected as if by the \*^O\*^N command. If a left-click is performed with the mouse cursor on an OSC 8 hyperlink -which is already selected, the hyperlink is opened as if by the \(haO\(haO command. +which is already selected, the hyperlink is opened as if by the \*^O\*^O command. The number of lines to scroll when the wheel is moved -can be set by the \-\-wheel-lines option. +can be set by the +.B "\-\-wheel\-lines" +option. Mouse input works only on terminals which support X11 mouse reporting, -and on the Windows version of -.BR less . -.IP "\-\-MOUSE" -Like \-\-mouse, except the direction scrolled +and on Windows. +.IP "\fB\-\-MOUSE\fP" +Like +.BR "\-\-mouse" "," +except the direction scrolled on mouse wheel movement is reversed. -.IP "\-\-no-edit-warn" +.IP "\fB\-\-no\-edit\-warn\fP" Don't print a warning message when using the v command on a file which was opened using a LESSOPEN preprocessor (see the INPUT PREPROCESSOR section below). -.IP "\-\-no-keypad" +.IP "\fB\-\-no\-keypad\fP" Disables sending the keypad initialization and deinitialization strings to the terminal. This is sometimes useful if the keypad strings make the numeric keypad behave in an undesirable manner. -.IP "\-\-no-histdups" +.IP "\fB\-\-no\-histdups\fP" This option changes the behavior so that if a search string or file name is typed in, and the same string is already in the history list, the existing copy is removed from the history list before the new one is added. Thus, a given string will appear only once in the history list. Normally, a string may appear multiple times. -.IP "\-\-no-number-headers" -Header lines (defined via the \-\-header option) are not assigned line numbers. +.IP "\fB\-\-no\-number\-headers\fP" +Header lines (defined via the +.B "\-\-header" +option) are not assigned line numbers. Line number 1 is assigned to the first line after any header lines. -.IP "\-\-no-paste" -If the terminal supports xterm-compatible "bracketed paste", -any text pasted into +.IP "\fB\-\-no\-paste\fP" +If the terminal supports +.BR xterm -compatible +"bracketed paste", any text pasted into .B less is ignored, except that one line of text may be pasted into the command line at the bottom of the screen (search strings, file names, etc). That is, the first newline of text pasted into the command line and any text that follows it is ignored. -.IP "\-\-no-search-header-lines" +.IP "\fB\-\-no\-search\-header\-lines\fP" Searches do not include header lines, but still include header columns. -.IP "\-\-no-search-header-columns" +.IP "\fB\-\-no\-search\-header\-columns\fP" Searches do not include header columns, but still include header lines. -.IP "\-\-no-search-headers" +.IP "\fB\-\-no\-search\-headers\fP" Searches do not include header lines or header columns. -.IP "\-\-no-vbell" +.IP "\fB\-\-no\-vbell\fP" Disables the terminal's visual bell. -.IP "\-\-proc-backspace" -If set, backspaces are handled as if neither the \-u option -nor the \-U option were set. +.IP "\fB\-\-proc\-backspace\fP" +If set, backspaces are handled as if neither the +.B "\-u" +option +nor the +.B "\-U" +option were set. That is, a backspace adjacent to an underscore causes text to be displayed in underline mode, and a backspace between identical characters cause text to be displayed in boldface mode. -This option overrides the \-u and \-U options, so that display of +This option overrides the +.B "\-u" +and +.B "\-U" +options, so that display of backspaces can be controlled separate from tabs and carriage returns. -If not set, backspace display is controlled by the \-u and \-U options. -.IP "\-\-PROC-BACKSPACE" -If set, backspaces are handled as if the \-U option were set; +If not set, backspace display is controlled by the +.B "\-u" +and +.B "\-U" +options. +.IP "\fB\-\-PROC\-BACKSPACE\fP" +If set, backspaces are handled as if the +.B "\-U" +option were set; that is backspaces are treated as control characters. -.IP "\-\-proc-return" -If set, carriage returns are handled as if neither the \-u option -nor the \-U option were set. +.IP "\fB\-\-proc\-return\fP" +If set, carriage returns are handled as if neither the +.B "\-u" +option +nor the +.B "\-U" +option were set. That is, a carriage return immediately before a newline is deleted. -This option overrides the \-u and \-U options, so that display of +This option overrides the +.B "\-u" +and +.B "\-U" +options, so that display of carriage returns can be controlled separate from that of backspaces and tabs. -If not set, carriage return display is controlled by the \-u and \-U options. -.IP "\-\-PROC-RETURN" -If set, carriage returns are handled as if the \-U option were set; +If not set, carriage return display is controlled by the +.B "\-u" +and +.B "\-U" +options. +.IP "\fB\-\-PROC\-RETURN\fP" +If set, carriage returns are handled as if the +.B "\-U" +option were set; that is carriage returns are treated as control characters. -.IP "\-\-proc-tab" -If set, tabs are handled as if the \-U option were not set. +.IP "\fB\-\-proc\-tab\fP" +If set, tabs are handled as if the +.B "\-U" +option were not set. That is, tabs are expanded to spaces. -This option overrides the \-U option, so that display of +This option overrides the +.B "\-U" +option, so that display of tabs can be controlled separate from that of backspaces and carriage returns. -If not set, tab display is controlled by the \-U option. -.IP "\-\-PROC-TAB" -If set, tabs are handled as if the \-U option were set; +If not set, tab display is controlled by the +.B "\-U" +option. +.IP "\fB\-\-PROC\-TAB\fP" +If set, tabs are handled as if the +.B "\-U" +option were set; that is tabs are treated as control characters. -.IP "\-\-redraw-on-quit" +.IP "\fB\-\-redraw\-on\-quit\fP" When quitting, after sending the terminal deinitialization string, redraws the entire last screen. On terminals whose terminal deinitialization string causes the @@ -1554,65 +1966,85 @@ terminal to switch from an alternate screen, this makes the last screenful of the current file remain visible after .B less has quit. -.IP "\-\-rscroll=\fIc\fP" +.IP "\fB\-\-rscroll=\fP\fIc\fP" This option changes the character used to mark truncated lines. It may begin with a two-character attribute indicator like LESSBINFMT does. If there is no attribute indicator, standout is used. If set to "\-", truncated lines are not marked. -.IP "\-\-save-marks" +.IP "\fB\-\-save\-marks\fP" Save marks in the history file, so marks are retained across different invocations of .BR less . -.IP "\-\-search-options=\fI...\fP" +.IP "\fB\-\-search\-options=\fP\fI...\fP" Sets default search modifiers. The value is a string of one or more of the characters E, F, K, N, R or W. Setting any of these has the same effect as typing that control character at the beginning of every search pattern. -For example, setting \-\-search-options=W is the same as -typing \(haW at the beginning of every pattern. +For example, setting +.B "\-\-search\-options=\fIW\fP" +is the same as +typing \*^W at the beginning of every pattern. The value may also contain a digit between 1 and 5, -which has the same effect as typing \(haS followed by that digit +which has the same effect as typing \*^S followed by that digit at the beginning of every search pattern. -The value "-" disables all default search modifiers. -.IP "\-\-show-preproc-errors" -If a preprocessor produces data, +The value "\-" disables all default search modifiers. +.IP "\fB\-\-show\-preproc\-errors\fP" +If a LESSOPEN preprocessor produces data, then exits with a non-zero exit code, .B less will display a warning. -.IP "\-\-status-col-width=\fIn\fP" -Sets the width of the status column when the \-J option is in effect. +.IP "\fB\-\-status\-col\-width=\fP\fIn\fP" +Sets the width of the status column when the +.B "\-J" +option is in effect. The default is 2 characters. -.IP "\-\-status-line" +.IP "\fB\-\-status\-line\fP" If a line is marked, the entire line (rather than just the status column) is highlighted. -Also lines highlighted due to the \-w option will have +Also lines highlighted due to the +.B "\-w" +option will have the entire line highlighted. -If \-\-use-color is set, the line is colored rather than highlighted. -.IP "\-\-use-backslash" +If +.B "\-\-use\-color" +is set, the line is colored rather than highlighted. +.IP "\fB\-\-use\-backslash\fP" This option changes the interpretations of options which follow this one. -After the \-\-use-backslash option, any backslash in an option string is +After the +.B "\-\-use\-backslash" +option, any backslash in an option string is removed and the following character is taken literally. This allows a dollar sign to be included in option strings. -.IP "\-\-use-color" +.IP "\fB\-\-use\-color\fP" Enables colored text in various places. -The \-D option can be used to change the colors. +The +.B "\-D" +option can be used to change the colors. Colored text works only if the terminal supports ANSI color escape sequences (as defined in .nh -https://www.ecma-international.org/publications-and-standards/standards/ecma-48). +https://\*:www\*:.ecma\-international\*:.org/\*:publications\-and\-standards/\*:standards/\*:ecma\-48). .hy -.IP "\-\-wheel-lines=\fIn\fP" +.IP "\fB\-\-wheel\-lines=\fP\fIn\fP" Set the number of lines to scroll when the mouse wheel is scrolled -and the \-\-mouse or \-\-MOUSE option is in effect. +and the +.B "\-\-mouse" +or +.B "\-\-MOUSE" +option is in effect. The default is 1 line. -.IP "\-\-wordwrap" -When the \-S option is not in use, +.IP "\fB\-\-wordwrap\fP" +When the +.B "\-S" +option is not in use, wrap each line at a space or tab if possible, so that a word is not split between two lines. The default is to wrap at any character. -.IP \-\- -A command line argument of "\-\-" marks the end of option arguments. +.IP \fB\-\-\fP +A command line argument of +.RB "\[dq]" "\-\-" "\[dq]" +marks the end of option arguments. Any arguments following this are interpreted as filenames. This can be useful when viewing a file whose name begins with a "\-" or "+". Otherwise, option arguments and filename arguments can be intermixed; @@ -1633,7 +2065,9 @@ If the option starts with ++, the initial command applies to every file being viewed, not just the first one. The + command described previously may also be used to set (or change) an initial command for every file. -Also see the \-\-cmd option. +Also see the +.B "\-\-cmd" +option. . .SH "LINE EDITING" When entering a command line at the bottom of the screen @@ -1645,16 +2079,16 @@ a key does not exist on a particular keyboard. (Note that the forms beginning with ESC do not work on some MS-DOS and Windows systems because ESC is the line erase character.) Any of these special keys may be entered literally by preceding -it with the "literal" character, either \(haV or \(haA. +it with the "literal" character, either \*^V or \*^A. A backslash itself may also be entered literally by entering two backslashes. .IP "LEFTARROW [ ESC-h ]" Move the cursor one space to the left. .IP "RIGHTARROW [ ESC-l ]" Move the cursor one space to the right. -.IP "\(haLEFTARROW [ ESC-b or ESC-LEFTARROW ]" +.IP "\*^LEFTARROW [ ESC-b or ESC-LEFTARROW ]" (That is, CONTROL and LEFTARROW simultaneously.) Move the cursor one word to the left. -.IP "\(haRIGHTARROW [ ESC-w or ESC-RIGHTARROW ]" +.IP "\*^RIGHTARROW [ ESC-w or ESC-RIGHTARROW ]" (That is, CONTROL and RIGHTARROW simultaneously.) Move the cursor one word to the right. .IP "HOME [ ESC-0 ]" @@ -1666,10 +2100,10 @@ Delete the character to the left of the cursor, or cancel the command if the command line is empty. .IP "DELETE or [ ESC-x ]" Delete the character under the cursor. -.IP "\(haBACKSPACE [ ESC-BACKSPACE ]" +.IP "\*^BACKSPACE [ ESC-BACKSPACE ]" (That is, CONTROL and BACKSPACE simultaneously.) Delete the word to the left of the cursor. -.IP "\(haDELETE [ ESC-X or ESC-DELETE ]" +.IP "\*^DELETE [ ESC-X or ESC-DELETE ]" (That is, CONTROL and DELETE simultaneously.) Delete the word under the cursor. .IP "UPARROW [ ESC-k ]" @@ -1689,18 +2123,18 @@ If the completed filename is a directory, a "/" is appended to the filename. (On MS-DOS and Windows systems, a "\e" is appended.) The environment variable LESSSEPARATOR can be used to specify a different character to append to a directory name. -.IP "BACKTAB [ ESC-TAB ]" -Like, TAB, but cycles in the reverse direction thru the matching filenames. -.IP "\(haL" +.IP "BACKTAB (SHIFT-TAB) [ ESC-TAB ]" +Like TAB, but cycles in the reverse direction thru the matching filenames. +.IP "\*^L" Complete the partial filename to the left of the cursor. If it matches more than one filename, all matches are entered into the command line (if they fit). -.IP "\(haU (Unix and OS/2) or ESC (MS-DOS and Windows)" +.IP "\*^U (Unix and OS/2) or ESC (MS-DOS and Windows)" Delete the entire command line, or cancel the command if the cursor is at the beginning of the command line. If you have changed your line-kill character in Unix to something -other than \(haU, that character is used instead of \(haU. -.IP "\(haG" +other than \*^U, that character is used instead of \*^U. +.IP "\*^G" Delete the entire command line and return to the main prompt. . .SH "KEY BINDINGS" @@ -1950,8 +2384,8 @@ preceding character. (Only when LESSCHARSET is "utf8".) are simply deleted from the input and not displayed. (Only when LESSCHARSET is "utf8".) .PP -A "character set" is simply a description of which characters are to -be considered normal, control, and binary. +A "character set" is a description of which of these categories +each character belongs to. The LESSCHARSET environment variable may be used to select a character set. Possible values for LESSCHARSET are: .IP ascii @@ -1970,16 +2404,16 @@ Same as iso8859. Selects a character set appropriate for MS-DOS. .IP ebcdic Selects an EBCDIC character set. -.IP IBM-1047 +.IP IBM\-1047 Selects an EBCDIC character set used by OS/390 Unix Services. This is the EBCDIC analogue of latin1. You get similar results -by setting either LESSCHARSET=IBM-1047 or LC_CTYPE=en_US +by setting either LESSCHARSET=IBM\-1047 or LC_CTYPE=en_US in your environment. -.IP koi8-r +.IP koi8\-r Selects a Russian character set. .IP next Selects a character set appropriate for NeXT computers. -.IP utf-8 +.IP utf\-8 Selects the UTF-8 encoding of the ISO 10646 character set. UTF-8 is special in that it supports multi-byte characters in the input file. It is the only character set that supports multi-byte characters. @@ -2013,22 +2447,22 @@ ascii 8bcccbcc18b95.b dos 8bcccbcc12bc5b95.b. ebcdic 5bc6bcc7bcc41b.9b7.9b5.b..8b6.10b6.b9.7b 9.8b8.17b3.3b9.7b9.8b8.6b10.b.b.b. -IBM-1047 4cbcbc3b9cbccbccbb4c6bcc5b3cbbc4bc4bccbc +IBM\-1047 4cbcbc3b9cbccbccbb4c6bcc5b3cbbc4bc4bccbc 191.b iso8859 8bcccbcc18b95.33b. -koi8-r 8bcccbcc18b95.b128. +koi8\-r 8bcccbcc18b95.b128. latin1 8bcccbcc18b95.33b. next 8bcccbcc18b95.bb125.bb .TE .RE .PP If neither LESSCHARSET nor LESSCHARDEF is set, -but any of the strings "UTF-8", "UTF8", "utf-8" or "utf8" +but any of the strings "UTF\-8", "UTF8", "utf\-8" or "utf8" is found in the LC_ALL, LC_CTYPE or LANG -environment variables, then the default character set is utf-8. +environment variables, then the default character set is utf\-8. .PP If that string is not found, but your system supports the -.B setlocale +.BR setlocale (3) interface, .B less will use setlocale to determine the character set. @@ -2036,12 +2470,12 @@ setlocale is controlled by setting the LANG or LC_CTYPE environment variables. .PP Finally, if the -.I setlocale -interface is also not available, the default character set is utf-8. +.B setlocale +interface is also not available, the default character set is utf\-8. .PP Control and binary characters are displayed in standout (reverse video). Each such character is displayed in caret notation if possible -(e.g.\& \(haA for control-A). Caret notation is used only if +(e.g.\& \*^A for control-A). Caret notation is used only if inverting the 0100 bit results in a normal printable character. Otherwise, the character is displayed as a hex number in angle brackets. This format can be changed by @@ -2059,7 +2493,7 @@ The default if no LESSBINFMT is specified is "*s<%02X>". Warning: the result of expanding the character via LESSBINFMT must be less than 31 characters. .PP -When the character set is utf-8, the LESSUTFBINFMT environment variable +When the character set is utf\-8, the LESSUTFBINFMT environment variable acts similarly to LESSBINFMT but it applies to Unicode code points that were successfully decoded but are unsuitable for display (e.g., unassigned code points). @@ -2074,7 +2508,7 @@ and stray trailing octets) are displayed individually using LESSBINFMT so as to facilitate diagnostic of how the UTF-8 file is ill-formed. .PP -When the character set is utf-8, in rare cases it may be desirable to +When the character set is utf\-8, in rare cases it may be desirable to override the Unicode definition of the type of certain characters. For example, characters in a Private Use Area are normally treated as binary characters, but if you are using a custom font with printable characters @@ -2108,32 +2542,39 @@ A deleted character (deleted from the input and not displayed). .RE .PP For example, setting LESSUTFCHARDEF to +.PP +.EX .nf -.sp - E000-F8FF:p,F0000-FFFFD:p,100000-10FFFD:p -.sp + E000\-F8FF:p,F0000\-FFFFD:p,100000\-10FFFD:p .fi +.EE +.PP would make all Private Use Area characters be treated as printable. .PP By default, emoji modifiers, components and variation selectors are deleted because many terminals do not display them correctly. If you use a terminal which does display some or all of them correctly, -you can cause to be displayed by setting LESSUTFCHARDEF +you can cause them to be displayed by setting LESSUTFCHARDEF to treat them as composing characters. For example, this sets them all to composing characters: +.PP +.EX .nf -.sp - FE00-FE0F:c,1F3FB-1F3FF:c,1F9B0-1F9B3:c,E0100-E01EF:c -.sp + FE00\-FE0F:c,1F3FB\-1F3FF:c,1F9B0\-1F9B3:c,E0100\-E01EF:c .fi +.EE .SH "PROMPTS" -The \-P option allows you to tailor the prompt to your preference. -The string given to the \-P option replaces the specified prompt string. +The +.B "\-P" +option allows you to tailor the prompt to your preference. +The string given to the +.B "\-P" +option replaces the specified prompt string. Certain characters in the string are interpreted specially. The prompt mechanism is rather complicated to provide flexibility, but the ordinary user need not understand the details of constructing personalized prompt strings. -.sp +.PP A percent sign followed by a single character is expanded according to what the following character is. (References to the input file size below refer to the preprocessed size, @@ -2147,11 +2588,16 @@ display is used, an "m" means use the middle line, a "b" means use the bottom line, a "B" means use the line just after the bottom line, -and a "j" means use the "target" line, as specified by the \-j option. +and a "j" means use the "target" line, as specified by the +.B "\-j" +option. .IP "%B" Replaced by the size of the current input file. .IP "%c" -Replaced by the column number of the text appearing in the first +Replaced by the column number of the text which appears in the first +column of the screen. +.IP "%C" +Replaced by the column number of the text which appears (or would appear) in the last column of the screen. .IP "%d\fIX\fP" Replaced by the page number of a line in the input file. @@ -2184,13 +2630,18 @@ Replaced by the total number of input files. .IP "%o" Replaced by the URI of the currently selected OSC 8 hyperlink, or a question mark if no hyperlink is selected. -This is used by OSC 8 handlers as explained in the \(haO\(haO command description. +This is used by OSC 8 handlers as explained in the \*^O\*^O command description. .IP "%p\fIX\fP" Replaced by the percent into the current input file, based on byte offsets. The line used is determined by the \fIX\fP as with the %b option. .IP "%P\fIX\fP" Replaced by the percent into the current input file, based on line numbers. The line used is determined by the \fIX\fP as with the %b option. +.IP "%Q" +Replaced by the percent of the last column of text displayed on the screen +compared to the length of the longest line currently displayed +(that is, %C divided by %W). +Note that using this sequence can make displaying the prompt be slower than usual. .IP "%s" Same as %B. .IP "%t" @@ -2198,8 +2649,13 @@ Causes any trailing spaces to be removed. Usually used at the end of the string, but may appear anywhere. .IP "%T" Normally expands to the word "file". -However if viewing files via a tags list using the \-t option, +However if viewing files via a tags list using the +.B "\-t" +option, it expands to the word "tag". +.IP "%W" +Replaced by the width of the longest line currently displayed on the screen. +Note that using this sequence can make displaying the prompt be slower than usual. .IP "%x" Replaced by the name of the next input file in the list. .PP @@ -2247,6 +2703,9 @@ of the specified line is known. .IP "?P\fIX\fP" True if the percent into the current input file, based on line numbers, of the specified line is known. +.IP "?Q" +True if %Q is less than 100. +Note that using this sequence can make displaying the prompt be slower than usual. .IP "?s" Same as "?B". .IP "?x" @@ -2260,14 +2719,18 @@ Any of the special characters may be included in the prompt literally by preceding it with a backslash. .PP Some examples: -.sp +.PP +.EX ?f%f:Standard input. -.sp +.EE +.PP This prompt prints the filename, if known; otherwise the string "Standard input". -.sp -?f%f \&.?ltLine %lt:?pt%pt\e%:?btByte %bt:-... -.sp +.PP +.EX +?f%f \&.?ltLine %lt:?pt%pt\e%:?btByte %bt:\-... +.EE +.PP This prompt would print the filename, if known. The filename is followed by the line number, if known, otherwise the percent if known, otherwise the byte offset if known. @@ -2275,9 +2738,11 @@ Otherwise, a dash is printed. Notice how each question mark has a matching period, and how the % after the %pt is included literally by escaping it with a backslash. -.sp -?n?f%f\ .?m(%T %i of %m)\ ..?e(END)\ ?x-\ Next\e:\ %x..%t -.sp +.PP +.EX +?n?f%f\ .?m(%T %i of %m)\ ..?e(END)\ ?x\-\ Next\e:\ %x..%t +.EE +.PP This prints the filename if this is the first prompt in a file, followed by the "file N of N" message if there is more than one input file. @@ -2286,34 +2751,44 @@ followed by the name of the next file, if there is one. Finally, any trailing spaces are truncated. This is the default prompt. For reference, here are the defaults for -the other two prompts (\-m and \-M respectively). +the other two prompts +.B "\-m" +and +.B "\-M" +respectively). Each is broken into two lines here for readability only. +.PP +.EX .nf -.sp -?n?f%f\ .?m(%T\ %i\ of\ %m)\ ..?e(END)\ ?x-\ Next\e:\ %x.: +?n?f%f\ .?m(%T\ %i\ of\ %m)\ ..?e(END)\ ?x\-\ Next\e:\ %x.: ?pB%pB\e%:byte\ %bB?s/%s...%t -.sp -?f%f\ .?n?m(%T\ %i\ of\ %m)\ ..?ltlines\ %lt-%lb?L/%L.\ : - byte\ %bB?s/%s.\ .?e(END)\ ?x-\ Next\e:\ %x.:?pB%pB\e%..%t -.sp +.PP +?f%f\ .?n?m(%T\ %i\ of\ %m)\ ..?ltlines\ %lt\-%lb?L/%L.\ : + byte\ %bB?s/%s.\ .?e(END)\ ?x\-\ Next\e:\ %x.:?pB%pB\e%..?c\ (column\ %c).%t .fi +.EE +.PP And here is the default message produced by the = command: +.PP +.EX .nf -.sp -?f%f\ .?m(%T\ %i\ of\ %m)\ .?ltlines\ %lt-%lb?L/%L.\ . - byte\ %bB?s/%s.\ ?e(END)\ :?pB%pB\e%..%t +?f%f\ .?m(%T\ %i\ of\ %m)\ .?ltlines\ %lt\-%lb?L/%L.\ . + byte\ %bB?s/%s.\ ?e(END)\ :?pB%pB\e%..?c\ (column\ %c).%t .fi +.EE .PP The prompt expansion features are also used for another purpose: if an environment variable LESSEDIT is defined, it is used as the command to be executed when the v command is invoked. The LESSEDIT string is expanded in the same way as the prompt strings. The default value for LESSEDIT is: +.PP +.EX .nf -.sp %E\ ?lm+%lm.\ %g -.sp .fi +.EE +.PP Note that this expands to the editor name, followed by a + and the line number, followed by the shell-escaped file name. If your editor does not accept the "+linenumber" syntax, or has other @@ -2332,17 +2807,21 @@ the examine command (:e) .IP "glob" metacharacters such as * in filenames, .br -and filename completion (TAB, \(haL) +and filename completion (TAB, \*^L) .IP "history" history file .IP "lesskey" -use of lesskey files (-k and \-\-lesskey-src) +use of lesskey files +.B "\-k" +and +.BR "\-\-lesskey\-src" ")" .IP "lessopen" input preprocessor (LESSOPEN environment variable) .IP "logfile" -log files (s and \-o) +log files (s and +.BR "\-o" ")" .IP "osc8" -opening OSC 8 links (\(haO\(haO) +opening OSC 8 links (\*^O\*^O) .IP "pipe" the pipe command (|) .IP "shell" @@ -2352,7 +2831,8 @@ stopping .B less via a SIGTSTP signal .IP "tags" -use of tags files (-t) +use of tags files +.RB "(" "\-t" ")" .PP The LESSSECURE_ALLOW environment variable can be set to a comma-separated list of names of features which are selectively enabled when LESSSECURE is set. @@ -2380,25 +2860,51 @@ and the environment variable LESS_IS_MORE is not set to 0, behaves (mostly) in conformance with the POSIX .BR more (1) command specification. -In this mode, less behaves differently in these ways: +In this mode, +.B less +behaves differently in these ways: .PP -The \-e option works differently. -If the \-e option is not set, +The +.B "\-e" +option works differently. +If the +.B "\-e" +option is not set, .B less -behaves as if the \-e option were set. -If the \-e option is set, +behaves as if the +.B "\-e" +option were set. +If the +.B "\-e" +option is set, .B less -behaves as if the \-E option were set. +behaves as if the +.B "\-E" +option were set. .PP -The \-m option works differently. -If the \-m option is not set, the medium prompt is used, +The +.B "\-m" +option works differently. +If the +.B "\-m" +option is not set, the medium prompt is used, and it is prefixed with the string "\-\-More\-\-". -If the \-m option is set, the short prompt is used. +If the +.B "\-m" +option is set, the short prompt is used. .PP -The \-n option acts like the \-z option. -The normal behavior of the \-n option is unavailable in this mode. +The +.B "\-n" +option acts like the +.B "\-z" +option. +The normal behavior of the +.B "\-n" +option is unavailable in this mode. .PP -The parameter to the \-p option is taken to be a +The parameter to the +.B "\-p" +option is taken to be a .B less command rather than a search pattern. .PP @@ -2445,10 +2951,12 @@ Characters which may end an ANSI color escape sequence .IP LESSANSIMIDCHARS Characters which may appear between the ESC character and the end character in an ANSI color escape sequence -(default "0123456789:;[?!"\(aq#%()*+\ "). +(default "0123456789:;[?!"\*'#%()*+\ "). .IP LESSANSIOSCALLOW A comma-separated list of OSC types which are output directly to the -terminal when \-R is in effect +terminal when +.B "\-R" +is in effect (default "8"; that is, only OSC 8 sequences are output directly). .IP LESSANSIOSCCHARS Characters which may follow an ESC character to mark the start @@ -2477,7 +2985,9 @@ in filenames on Unix systems. Editor prototype string (used for the v command). See discussion under PROMPTS. .IP LESSGLOBALTAGS -Name of the command used by the \-t option to find global tags. +Name of the command used by the +.B "\-t" +option to find global tags. Normally should be set to "global" if your system has the .BR global (1) command. If not set, global tags are not used. @@ -2508,7 +3018,9 @@ Name of the default .I "lesskey binary" file. (Not used if "$LESSKEYIN" exists.) .IP LESSKEY_CONTENT -The value is parsed as if it were the parameter of a \-\-lesskey-content option. +The value is parsed as if it were the parameter of a +.B "\-\-lesskey\-content" +option. .IP LESSKEYIN_SYSTEM Name of the default system-wide .I "lesskey source" @@ -2521,7 +3033,15 @@ file. (Not used if "$LESSKEYIN_SYSTEM" exists.) List of characters which are considered "metacharacters" by the shell. .IP LESSMETAESCAPE Prefix which less will add before each metacharacter in a -command sent to the shell (default "\\"). +command sent to the shell (default "\e"). +.IP LESSNOCONFIG +If set to "\-", all environment variables except TERM are ignored +(treated as if they were not set). +If set to a comma-separated list of environment variable names, +all environment variables except TERM and those in the list are ignored. +In either case (if set to any non-empty value), all +.B lesskey +files are also ignored. .IP LESSOPEN Command line to invoke the (optional) input-preprocessor. .IP LESSSECURE @@ -2532,7 +3052,7 @@ Enables individual features which are normally disabled by LESSSECURE. See discussion under SECURITY. .IP LESSSEPARATOR String to be appended to a directory name in filename completion -(default "\\" on MS-DOS, Windows, and OS/2; otherwise "/"). +(default "\e" on MS-DOS, Windows, and OS/2; otherwise "/"). .IP LESSUTFBINFMT Format for displaying non-printable Unicode code points. .IP LESSUTFCHARDEF @@ -2572,14 +3092,18 @@ sets an OSC 8 handler for opening OSC 8 links containing a URI with that scheme. Sets an OSC 8 handler for opening OSC 8 links for which there is no specific LESS_OSC8_xxx handler set for the "xxx" scheme. .IP LESS_SHELL_LINES -When the \-F option is set, +When the +.B "\-F" +option is set, .B less exits automatically if the number of screen lines used to display the file is less than or equal to the screen height minus the value of the LESS_SHELL_LINES variable. Thus, if you use a shell prompt which occupies more than one screen line, this variable can be set to the number of lines used by your prompt, -to ensure that the entire file can be seen when \-F is used. +to ensure that the entire file can be seen when +.B "\-F" +is used. If not set, LESS_SHELL_LINES is assumed to be 1. .IP LESS_SIGUSR1 If set to a string of one or more @@ -2590,14 +3114,31 @@ receives a SIGUSR1 signal. .IP LESS_TERMCAP_xx Where "xx" is any two characters, overrides the definition of the termcap "xx" capability for the terminal. +No escape sequences in the string are processed, so any +nonprintable characters such as ESC must be in the string literally. +.IP LESS_TERMINFO_xxxx +Where "xxxx" is any string of characters, overrides the definition +of the terminfo "xxxx" capability for the terminal. +You can use either LESS_TERMCAP_xx or LESS_TERMINFO_xxxx to override +a terminal capability, regardless of whether +.B less +is built with the +.B termcap +or the +.B terminfo +library. .IP LESS_TERMCAP_BRACKETED_PASTE_START Overrides the standard ANSI escape sequence to enable bracketed paste. -This is used when the \-\-no-paste option is in effect. +This is used when the +.B "\-\-no\-paste" +option is in effect. .IP LESS_TERMCAP_BRACKETED_PASTE_END Overrides the standard ANSI escape sequence to disable bracketed paste. .IP LESS_TERMCAP_MOUSE_START Overrides the standard ANSI escape sequence to enable mouse reporting. -This is used when the \-\-mouse option is in effect. +This is used when the +.B "\-\-mouse" +option is in effect. .IP LESS_TERMCAP_MOUSE_END Overrides the standard ANSI escape sequence to disable mouse reporting. .IP LESS_TERMCAP_SUSPEND @@ -2684,11 +3225,11 @@ Mark Nudelman .br Report bugs at .nh -https://github.com/gwsw/less/issues. +https://\*:github\*:.com/\*:gwsw/\*:less/\*:issues. .hy .br For more information, see the less homepage at .br .nh -https://greenwoodsoftware.com/less. +https://\*:greenwoodsoftware\*:.com/\*:less. .hy |