shell: Add --cwd.

* guix/scripts/environment.scm (show-environment-options-help): Document
--cwd.
(%options): Add cwd.
(launch-environment/container): Add cwd parameter.  Implement passing it to
the container.
(guix-environment*): Reject --cwd without --container.
* doc/guix.texi (Invoking guix shell): Document it.
* tests/guix-environment-container.sh: Add tests.
* tests/guix-shell.sh: Add tests.

Fixes: guix/guix# 7825
Change-Id: Iba4ff3d2058e92f504fbcbf688346357ce913213

1 files changed, 26 insertions, 0 deletions

diff --git a/doc/guix.texi b/doc/guix.texi
index b2ff12dcb1..50eddc426e 100644
--- a/doc/guix.texi
+++ b/doc/guix.texi
@@ -6591,6 +6591,21 @@ directory within the container.  If this is undesirable,
 be automatically shared and will change to the user's home directory
 within the container instead.  See also @option{--user}.
 
+@item --cwd=@var{directory}
+For containers, change to @var{directory} inside the container instead
+of the default location.  The default location is the current working
+directory when @option{--no-cwd} is not used, or the user's home
+directory when @option{--no-cwd} is used.  When @var{directory} is a
+relative file name, it is interpreted relative to the current working
+directory on the host.  Note that @option{--cwd} does not automatically
+share @var{directory}---you must ensure it is accessible via the default
+current directory sharing or explicit @option{--share}/@option{--expose}
+options.  For example:
+
+@example
+guix shell --container --cwd=/tmp --share=/tmp coreutils
+@end example
+
 @item --writable-root
 When using @option{--container}, this option makes the root file system
 writable (it is read-only by default).
@@ -7092,6 +7107,17 @@ directory within the container.  If this is undesirable,
 be automatically shared and will change to the user's home directory
 within the container instead.  See also @option{--user}.
 
+@item --cwd=@var{directory}
+For containers, change to @var{directory} inside the container instead
+of the default location.  The default location is the current working
+directory when @option{--no-cwd} is not used, or the user's home
+directory when @option{--no-cwd} is used.  When @var{directory} is a
+relative file name, it is interpreted relative to the current working
+directory on the host.  Note that @option{--cwd} does not automatically
+share @var{directory}---you must ensure it is accessible via the default
+current directory sharing or explicit @option{--share}/@option{--expose}
+options.
+
 @item --expose=@var{source}[=@var{target}]
 @itemx --share=@var{source}[=@var{target}]
 For containers, @option{--expose} (resp. @option{--share}) exposes the