1 files changed, 2 insertions, 1 deletions

diff --git a/src/callproc.c b/src/callproc.c
index 7b8ba8fea21..c720f3b2ff5 100644
--- a/src/callproc.c
+++ b/src/callproc.c
@@ -1665,7 +1665,8 @@ syms_of_callproc ()
 
   DEFVAR_LISP ("shell-file-name", &Vshell_file_name,
                doc: /* *File name to load inferior shells from.
-Initialized from the SHELL environment variable.  */);
+Initialized from the SHELL environment variable, or to /bin/sh
+if SHELL is not set.  */);
 
   DEFVAR_LISP ("exec-path", &Vexec_path,
                doc: /* *List of directories to search programs to run in subprocesses.