checkrun.sh - Error Notification for .timer Units

#!/bin/bash

# defaults
MAILER="sendmail"
MAILTO="$USER"
VERBOSE=0

# usage information
function print_usage() {
    echo "usage: $0 [OPTIONS] COMMAND"
    echo "options:"
    echo "    -s CMD     use CMD as mailer (default: sendmail)"
    echo "    -m MAILTO  set recipient for notification mail (default: \$USER)"
    echo "    -v         send command output even on exit code 0"
    echo "    -h         display this usage information"
}

# parse cmdline options
while getopts ":s:m:vh" OPT; do
    case $OPT in
        s)
            MAILER="$OPTARG"
            ;;
        m)
            MAILTO="$OPTARG"
            ;;
        v)
            VERBOSE=1
            ;;
        h)
            print_usage
            exit 0
            ;;
        \?)
            echo "Invalid option: -$OPTARG." >&2
            exit 1
            ;;
        :)
            echo "Option -$OPTARG requires an argument." >&2
            exit 1
            ;;
    esac
done
shift $(( $OPTIND - 1 ))

# check for COMMAND
if [ -z "$1" ]; then
    echo "error: missing argument."
    print_usage
    exit 1
fi

# execute COMMAND, capture output
LOG="$(mktemp)"
$1 &> "$LOG"
ERR=$?

# evaluate return value
if [ $ERR -ne 0 ]; then
    echo -e "Subject: '$1' FAILED ($ERR)\r\n" | cat - "$LOG" | $MAILER "$MAILTO"
    cat "$LOG"
    exit $ERR
fi

# notify if output was given and verbose mode selected
if [ $VERBOSE -eq 1 ] && [ $(wc -l "$LOG" | cut -d ' ' -f 1) -gt 0 ]; then
    echo -e "Subject: '$1'\r\n" | cat - "$LOG" | $MAILER "$MAILTO"
fi

# clean up
rm -f "$LOG"

exit 0