Allow using '$HOSTNAME' in @resurrect-dir

Closes #197

CHANGELOG.md

@@ -19,6 +19,7 @@
 - added guide for migrating from tmuxinator
 - fixed a bug for restoring commands on tmux 2.5 (and probably tmux 2.4)
 - do not create another resurrect file if there are no changes (credit @vburdo)
+- allow using '$HOSTNAME' in @resurrect-dir
 
 ### v2.4.0, 2015-02-23
 - add "tmux-test"

docs/save_dir.md

@@ -4,3 +4,12 @@ By default Tmux environment is saved to a file in `~/.tmux/resurrect` dir.
 Change this with:
 
     set -g @resurrect-dir '/some/path'
+
+Using environment variables or shell interpolation in this option is not
+allowed as the string is used literally. So the following won't do what is
+expected:
+
+    set -g @resurrect-dir '/path/$MY_VAR/$(some_executable)'
+
+Only the following variables and special chars are allowed:
+`$HOME`, `$HOSTNAME`, and `~`.

scripts/helpers.sh

@@ -98,11 +98,13 @@ pane_content_files_restore_from_archive() {
 resurrect_dir() {
 	if [ -z "$_RESURRECT_DIR" ]; then
 		local path="$(get_tmux_option "$resurrect_dir_option" "$default_resurrect_dir")"
-		echo "${path/#\~/$HOME}" # expands tilde if used with @resurrect-dir
+		# expands tilde, $HOME and $HOSTNAME if used in @resurrect-dir
+		echo "$path" | sed "s,\$HOME,$HOME,g; s,\$HOSTNAME,$(hostname),g; s,\~,$HOME,g"
 	else
 		echo "$_RESURRECT_DIR"
 	fi
 }
+_RESURRECT_DIR="$(resurrect_dir)"
 
 resurrect_file_path() {
 	if [ -z "$_RESURRECT_FILE_PATH" ]; then
@@ -112,6 +114,7 @@ resurrect_file_path() {
 		echo "$_RESURRECT_FILE_PATH"
 	fi
 }
+_RESURRECT_FILE_PATH="$(resurrect_file_path)"
 
 last_resurrect_file() {
 	echo "$(resurrect_dir)/last"