set-exim4-update-conf

#!/bin/bash
set -e

conf='/etc/exim4/update-exim4.conf.conf'

sedExpr=''
while [ $# -gt 0 ]; do
	key="$1"
	value="$2"
	shift 2
	
	if ! grep -qE "^#?${key}=" "$conf"; then
		echo >&2 "error: '$key' not found in '$conf'"
		exit 1
	fi
	
	sed_escaped_value="$(echo "$value" | sed 's/[\/&]/\\&/g')"
	sedExpr+=$'\n\t'"s/^#?(${key})=.*/\1='${sed_escaped_value}'/;"
done

set -x
sed -ri "$sedExpr"$'\n' "$conf"
update-exim4.conf -v