work-n-rest.sh - a POSIX shell script for executing long running tasks with pauses

work-n-rest.md

work-n-rest.sh

A POSIX shell script for executing long running tasks with pauses.

Usage examples

Work for 10 seconds, then rest for 10 seconds:

./work-n-rest.sh find ./ -name '*.log'

Work for 20 seconds, then rest for 5 seconds:

WORK=20 REST=5 ./work-n-rest.sh find ./ -name '*.log'

work-n-rest.sh

#!/bin/sh

set -eu

EX_USAGE=64

if [ $# -eq 0 ]; then
    printf 'Error: missing argument\nUsage: %s COMMAND\n' "$(basename "$0")" >&2
    exit $EX_USAGE
fi

WORK=${WORK:-10}
REST=${REST:-10}

eval "$* &"

PID=$!

killOrExit() {
    if ps --pid "$PID" > /dev/null; then
        kill -s "$1" "$PID"
    else
        wait $PID
        exit $?
    fi
}

while true; do
    sleep "$WORK"
    killOrExit STOP
    sleep "$REST"
    killOrExit CONT
done