Allow user to pick directory with "-d dir"

README

@@ -16,6 +16,8 @@ Shell scripts
 * shell:    Creates a shell for testing things in.
 
     Creates a "temporary interactive shell" with a temporary working
-    directory.  The working directory is removed when the shell exits
-    (unless the -k flag is used).  Useful for testing things in an
-    interactive environment other than your usual shell.
+    directory (unless the -d flag is used to specify an existing
+    directory) and clean environment.  The working directory is removed
+    when the shell exits (unless the -k or -d flag was used).  Useful
+    for testing things in an interactive environment other than your
+    usual shell.

TODO

@@ -2,8 +2,3 @@ For "shell":
 
     * Make it possible to pre-populate the temporary directory with the
       contents of an existing directory.
-
-    * Allow for multiple concurrent "shell" sessions in the same
-      temporary directory, possibly by giving the user the ablity to
-      manually pick the working directory (which would not be deleted
-      when exiting the session).

src/shell.in

@@ -19,10 +19,14 @@
 #
 # Example invocations:
 #
-#   $ shell         # starts a new shell (uses $SHELL)
-#   $ shell bash    # starts a new bash shell
-#   $ shell -k      # starts a new shell (uses $SHELL), temporary directory
-#                   # will not be deleted when exiting the session
+#   $ shell         # Starts a new shell (uses $SHELL).
+#   $ shell bash    # Starts a new bash shell.
+#   $ shell -k      # Starts a new shell (uses $SHELL).
+#                   # The temporary directory will not be deleted when
+#                   # exiting the session.
+#   $ shell -d dir  # Starts a new shell (uses $SHELL) with "dir"
+#                   # as the working directory.  The directory will not be
+#                   # deleted when exiting the session.
 
 _get_solaris_shells ()
 {
@@ -96,8 +100,10 @@ if [ "$_is_tmp_shell" = 'Yes' ]; then
     exit 1
 fi
 
-while getopts 'k' opt; do
+while getopts 'd:k' opt; do
     case "$opt" in
+        d) tmpcwd=$OPTARG
+           keep=1 ;;
         k) keep=1 ;;
         *) echo 'error in command line parsing' >&2
            exit 1
@@ -116,7 +122,10 @@ if [ -z "$realshell" ] || [ ! -x "$realshell" ]; then
     exit 1
 fi
 
-tmpcwd="$( mktemp -d -t "shell-$shell.XXXXXXXX" )"
+if [ -z "$tmpcwd" ]; then
+    tmpcwd="$( mktemp -d -t "shell-$shell.XXXXXXXX" )"
+fi
+
 if [ "$keep" -eq 1 ]; then
     trap 'printf "Leaving %s in place\n" "$tmpcwd" >&2' EXIT
 else