--- /dev/null
+#!/bin/bash
+# Copyright (C) 2014 Ian Kelling
+# This program is under GPL v. 3 or later, see <http://www.gnu.org/licenses/>
+
+appendu() {
+ local help="Usage: appendu [-h|--help] FILE
+
+Tee unique. Append each stdin line if it does not exist in the file
+
+ [-h|--help] display this message"
+
+
+ if [[ $1 == --help || $1 == -h ]]; then
+ echo "$help"
+ return
+ fi
+
+ if [[ ${#@} == 0 ]]; then
+ echo "error: need 1 or more arguments"
+ echo "$help"
+ return 1
+ fi
+
+ local MAPFILE
+ mapfile -t
+ for line in "${MAPFILE[@]}"; do
+ grep -xFq "$line" "$1" &>/dev/null || tee -a "$1" <<<"$line"
+ done
+ return 0
+}
+teeu "$@"