#!/bin/bash

# Given a filename, a regex pattern to match and a replacement string:
# If found, perform replacement, else append file w/replacement on new line.

grep $2 $1 >/dev/null
if [ $? -eq 0 ]; then
	# Pattern found; replace in file
	sed -i "s/$2/$3/g" $1 >/dev/null
else
	# Not found; append on new line (silently)
	echo $3 | sudo tee -a $1 >/dev/null
fi