freebsd-base.7: Add an example for unregistering

MFC after:		3 days
Reviewed by:		ivy, emaste
Discussed with:		bapt, des, emaste, ivy, phk, pi
Differential Revision:	https://reviews.freebsd.org/D55458

1 files changed, 35 insertions, 1 deletions

diff --git a/share/man/man7/freebsd-base.7 b/share/man/man7/freebsd-base.7
index aaa5a875df71..c690a7a9e0b9 100644
--- a/share/man/man7/freebsd-base.7
+++ b/share/man/man7/freebsd-base.7
@@ -14,7 +14,7 @@
 .\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 .\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 .\"
-.Dd February 26, 2026
+.Dd April 1, 2026
 .Dt FREEBSD-BASE 7
 .Os
 .Sh NAME
@@ -217,6 +217,39 @@ for a different target than the host system):
 pkg -r /ppcdev -oABI=FreeBSD:16:powerpc64le \e
     install FreeBSD-set-devel
 .Ed
+.Ss Unregister a currently running system
+Systems managed through
+.Xr pkg 8
+can be unregistered from the package manager \(em
+for example to upgrade in-place via
+.Dq make installworld .
+See
+.Xr build 7 .
+.Pp
+To unregister the base system from the package manager:
+.Bd -literal -offset indent
+pkg unregister -fg 'FreeBSD-\e*'
+.Ed
+.Pp
+Then, disable the base system package repository.
+If a configuration file was created in
+.Pa /usr/local/etc/pkg/repos/
+to enable base system packages, remove it:
+.Bd -literal -offset indent
+rm /usr/local/etc/pkg/repos/FreeBSD-base.conf
+.Ed
+.Pp
+Alternatively, if it is desired to keep it,
+edit the file and change
+.Dq Li enabled:
+to
+.Dq Li no
+to disable the entry.
+.Pp
+.Sy Warning :
+This is a destructive action
+which will prevent updating the base system via
+.Xr pkg 8 .
 .Sh SEE ALSO
 .Xr build 7 ,
 .Xr pkg 8 ,
@@ -225,3 +258,4 @@ pkg -r /ppcdev -oABI=FreeBSD:16:powerpc64le \e
 Support for installing the base system as packages was introduced in
 .Fx 15.0 .
 Earlier releases supported a subset of this functionality.
+Support for unregistering an existing installation appeared in pkg 2.5.