z plugin: allow usage while in sudo mode

plugins/z/z.sh

@@ -13,6 +13,7 @@
 #     set $_Z_NO_RESOLVE_SYMLINKS to prevent symlink resolution.
 #     set $_Z_NO_PROMPT_COMMAND if you're handling PROMPT_COMMAND yourself.
 #     set $_Z_EXCLUDE_DIRS to an array of directories to exclude.
+#     set $_Z_OWNER to your username if you want use z while sudo with $HOME kept
 #
 # USE:
 #   * z foo     # cd to most frecent dir matching foo
@@ -36,7 +37,7 @@ _z() {
  local datafile="${_Z_DATA:-$HOME/.z}"
 
  # bail out if we don't own ~/.z (we're another user but our ENV is still set)
- [ -f "$datafile" -a ! -O "$datafile" ] && return
+ [ -z "$_Z_OWNER" -a -f "$datafile" -a ! -O "$datafile" ] && return
 
  # add entries
  if [ "$1" = "--add" ]; then
@@ -54,6 +55,7 @@ _z() {
   # maintain the file
   local tempfile
   tempfile="$(mktemp "$datafile.XXXXXX")" || return
+  [ -n "$_Z_OWNER" ] && chown $_Z_OWNER:$(id -ng $_Z_OWNER) $tempfile
   while read line; do
    [ -d "${line%%\|*}" ] && echo $line
   done < "$datafile" | awk -v path="$*" -v now="$(date +%s)" -F"|" '