Make backup retention period configurable

For instance `tmux set-option -g @resurrect-delete-backup-after 1`
to only keep 1 day of backups.

Closes 252.

CHANGELOG.md

@@ -30,6 +30,8 @@
   e.g. `vim -S Session1.vim`.
 - Enable restoring command arguments for inline strategies with `*` character.
 - Kill session "0" if it wasn't restored.
+- Add `@resurrect-delete-backup-after` option to specify how many days of
+  backups to keep - default is 30.
 
 ### v2.4.0, 2015-02-23
 - add "tmux-test"

scripts/save.sh

@@ -269,11 +269,12 @@ dump_shell_history() {
 }
 
 remove_old_backups() {
-	# remove resurrect files older than 30 days, but keep at least 5 copies of backup.
+	# remove resurrect files older than 30 days (default), but keep at least 5 copies of backup.
+	local delete_after="$(get_tmux_option "$delete_backup_after_option" "$default_delete_backup_after")"
 	local -a files
 	files=($(ls -t $(resurrect_dir)/${RESURRECT_FILE_PREFIX}_*.${RESURRECT_FILE_EXTENSION} | tail -n +6))
 	[[ ${#files[@]} -eq 0 ]] ||
-		find "${files[@]}" -type f -mtime +30 -exec rm -v "{}" \;
+		find "${files[@]}" -type f -mtime "+${delete_after}" -exec rm -v "{}" \;
 }
 
 save_all() {

scripts/variables.sh

@@ -46,3 +46,6 @@ overwrite_option="@resurrect-never-overwrite"
 
 # Hooks are set via ${hook_prefix}${name}, i.e. "@resurrect-hook-post-save-all"
 hook_prefix="@resurrect-hook-"
+
+delete_backup_after_option="@resurrect-delete-backup-after"
+default_delete_backup_after="30" # days