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Diffstat (limited to 'release/picobsd/tinyware/msh/sh.1')
| -rw-r--r-- | release/picobsd/tinyware/msh/sh.1 | 261 |
1 files changed, 261 insertions, 0 deletions
diff --git a/release/picobsd/tinyware/msh/sh.1 b/release/picobsd/tinyware/msh/sh.1 new file mode 100644 index 000000000000..f19bce02cb7a --- /dev/null +++ b/release/picobsd/tinyware/msh/sh.1 @@ -0,0 +1,261 @@ +.TH SH 1 +.SH NAME +sh, ., break, case, cd, continue, eval, exec, exit, export, for, if, read, readonly, set, shift, trap, umask, wait, while \- shell +.SH SYNOPSIS +\fBsh\fR [\fB\-eiknqstvxu\fR] [\fB\-c \fIstr\fR] \fB[\fIfile\fR]\fR +.br +.de FL +.TP +\\fB\\$1\\fR +\\$2 +.. +.de EX +.TP 20 +\\fB\\$1\\fR +# \\$2 +.. +.SH OPTIONS +.FL "\-c" "Execute the commands in \fIstr\fR" +.FL "\-e" "Quit on error" +.FL "\-i" "Interactive mode; ignore QUIT, TERMINATE, INTERRUPT" +.FL "\-k" "Look for name=value everywhere on command line" +.FL "\-n" "Do not execute commands" +.FL "\-q" "Change qflag from sig_ign to sig_del" +.FL "\-s" "Read commands from standard input" +.FL "\-t" "Exit after reading and executing one command" +.FL "\-v" "Echo input lines as they are read" +.FL "\-x" "Trace" +.FL "\-u" "Unset variables" +.SH EXAMPLES +.EX "sh script" "Run a shell script" +.SH DESCRIPTION +.PP +.I Sh +is the shell, which forms the user's main interface with the system. +On startup, the shell reads /etc/profile and $HOME/.profile, if they exist, +and executes any commands they contain. The Minix shell has most of the +features of the V7 (Bourne) shell, including redirection of input and output, +pipes, magic characters, background processes, and shell scripts. A brief +summary follows, but whole books have been written on shell programming alone. +.LP +Some of the more common notations are: +.PP +.in +2.45i +.ta 2i 2.2i +.ti -2.2i +date # Regular command +.ti -2.2i +sort <file # Redirect \fIstdin\fR (standard input) +.ti -2.2i +sort <file1 >file2 # Redirect \fIstdin\fR and \fIstdout\fR +.ti -2.2i +cc file.c 2>error # Redirect \fIstderr\fR +.ti -2.2i +a.out >f 2>&1 # Combine standard output and standard error +.ti -2.2i +sort <file1 >>file2 # Append output to \fIfile2\fR +.ti -2.2i +sort <file1 >file2 & # Background job +.ti -2.2i +(ls \-l; a.out) & # Run two background commands sequentially +.ti -2.2i +sort <file | wc # Two-process pipeline +.ti -2.2i +sort <f | uniq | wc # Three-process pipeline +.ti -2.2i +ls \-l *.c # List all files ending in \fI.c\fR +.ti -2.2i +ls \-l [\fIa-c\fR]* # List all files beginning with \fIa\fR, \fIb\fR, or \fIc\fR +.ti -2.2i +ls \-l ? # List all one-character file names +.ti -2.2i +ls \e? # List the file whose name is question mark +.ti -2.2i +ls \(fm???\(fm # List the file whose name is three question marks +.ti -2.2i +v=/usr/ast # Set shell variable \fIv\fR +.ti -2.2i +ls \-l $v # Use shell variable \fIv\fR +.ti -2.2i +PS1=\(fmHi! \(fm # Change the primary prompt to \fIHi!\fR +.ti -2.2i +PS2=\(fmMore: \(fm # Change the secondary prompt to \fIMore:\fR +.ti -2.2i +ls \-l $HOME # List the home directory +.ti -2.2i +echo $PATH # Echo the search path +.ti -2.2i +echo $? # Echo exit status of previous command in decimal +.ti -2.2i +echo $$ # Echo shell's pid in decimal +.ti -2.2i +echo $! # Echo PID of last background process +.ti -2.2i +echo $# # Echo number of parameters (shell script) +.ti -2.2i +echo $2 # Echo second parameter (shell script) +.ti -2.2i +echo "$2" # Echo second parameter without expanding spaces +.ti -2.2i +echo $* # Echo all parameters (shell script) +.ti -2.2i +echo $@ # Echo all parameters (shell script) +.ti -2.2i +echo "$@" # Echo all parameters without expanding spaces +.in -2.45i +.LP +The shell uses the following variables for specific purposes: +.PP +.in +2.25i +.ta 2i +.ti -2i +SHELL the path of the current shell +.ti -2i +HOME the default value for the cd(1) command +.ti -2i +PATH the directories to be searched to find commands +.ti -2i +IFS the internal field separators for command strings +.ti -2i +PS1 the primary shell prompt +.ti -2i +PS2 the secondary shell prompt +.in -2.25i +.LP +There are various forms of substitution on the shell command line: +.PP +.in +2.25i +.ta 2i +.ti -2i +`...` Command string between back-quotes is replaced by its output +.ti -2i +"..." Permits variable substitution between quotes +.ti -2i +\&'...' Inhibits variable substitution between quotes +.ti -2i +$VAR Replaced by contents of variable VAR +.ti -2i +${VAR} Delimits variable VAR from any following string +.in -2.25i +.LP +The expressions below depend on whether or not VAR has ever been set. +If VAR has been set, they give: +.PP +.in +2.25i +.ta 2i +.ti -2i +${VAR-str} Replace expression by VAR, else by str +.ti -2i +${VAR=str} Replace expression by VAR, else by str and set VAR to str +.ti -2i +${VAR?str} Replace expression by VAR, else print str and exit shell +.ti -2i +${VAR+str} Replace expression by str, else by null string +.in -2.25i +.LP +If a colon is placed after VAR, the expressions depend on whether or not +VAR is currently set and non-null. +.LP +The shell has a number of built-in commands: +.PP +.in +2.25i +.ta 2i +.ti -2i +: return true status +.ti -2i +\&. fn execute shell script fn on current path +.ti -2i +break [n] break from a for, until or while loop; exit n levels +.ti -2i +continue [n] continue a for, until or while loop; resume nth loop +.ti -2i +cd [dir] change current working directory; move to $HOME +.ti -2i +eval cmd rescan cmd, performing substitutions +.ti -2i +eval rescan the current command line +.ti -2i +exec cmd execute cmd without creating a new process +.ti -2i +exec <|> with no command name, modify shell I/O +.ti -2i +exit [n] exit a shell program, with exit value n +.ti -2i +export [var] export var to shell's children; list exported variables +.ti -2i +pwd print the name of the current working directory +.ti -2i +read var read a line from stdin and assign to var +.ti -2i +readonly [var] make var readonly; list readonly variables +.ti -2i +set -f set shell flag (+f unsets flag) +.ti -2i +set str set positional parameter to str +.ti -2i +set show the current shell variables +.ti -2i +shift reassign positional parameters (except ${0}) one left +.ti -2i +times print accumulated user and system times for processes +.ti -2i +trap arg sigs trap signals sigs and run arg on receipt +.ti -2i +trap list trapped signals +.ti -2i +umask [n] set the user file creation mask; show the current umask +.ti -2i +wait [n] wait for process pid n; wait for all processes +.in -2.25i +.LP +The shell also contains a programming language, which has the following +operators and flow control statements: +.PP +.in +3.50i +.ta 2i 3.25i +.ti -3.25i +# Comment The rest of the line is ignored +.ti -3.25i += Assignment Set a shell variable +.ti -3.25i +&& Logical AND Execute second command only if first succeeds +.ti -3.25i +|| Logical OR Execute second command only if first fails +.ti -3.25i +(...) Group Execute enclosed commands before continuing +.in -3.50i +.PP +.in +2.25i +.ta 2i +.ti -2i +for For loop (for ... in ... do ... done) +.ti -2i +case Case statement ((case ... ) ... ;; ... esac) +.ti -2i +esac Case statement end +.ti -2i +while While loop (while ... do ... done) +.ti -2i +do Do/For/While loop start (do ... until ...) +.ti -2i +done For/While loop end +.ti -2i +if Conditional statement (if ... else ... elif ... fi) +.ti -2i +in For loop selection +.ti -2i +then Conditional statement start +.ti -2i +else Conditional statement alternative +.ti -2i +elif Conditional statement end +.ti -2i +until Do loop end +.ti -2i +fi Conditional statement end +.in -2.25i +.SH "SEE ALSO" +.BR echo (1), +.BR expr (1), +.BR pwd (1), +.BR true (1). |