doc: Clarify guix shell's DWIM behaviour.

* doc/guix.texi ("Invoking guix shell"): Document the exact behaviour, that is
which flags go together with which file names.

1 files changed, 11 insertions, 6 deletions

diff --git a/doc/guix.texi b/doc/guix.texi
index 05dbe8954e..c007c93dd3 100644
--- a/doc/guix.texi
+++ b/doc/guix.texi
@@ -5670,17 +5670,22 @@ before @command{guix shell} was invoked.  The next garbage collection
 (@pxref{Invoking guix gc}) may clean up packages that were installed in
 the environment and that are no longer used outside of it.
 
-As an added convenience, when running from a directory that contains a
-@file{manifest.scm} or a @file{guix.scm} file (in this order), possibly
-in a parent directory, @command{guix shell} automatically loads the
-file---provided the directory is listed in
-@file{~/.config/guix/shell-authorized-directories}, and only for
-interactive use:
+As an added convenience, @command{guix shell} will try to do what you
+mean when it is invoked interactively without any other arguments
+as in:
 
 @example
 guix shell
 @end example
 
+If it finds a @file{manifest.scm} in the current working directory or
+any of its parents, it uses this manifest as though it was given via @code{--manifest}.
+Likewise, if it finds a @file{guix.scm} in the same directories, it uses
+it to build a development profile as though both @code{--development}
+and @code{--file} were present.
+In either case, the file will only be loaded if the directory it
+resides in is listed in
+@file{~/.config/guix/shell-authorized-directories}.
 This provides an easy way to define, share, and enter development
 environments.