run some task every x second through cron

run-every-x-seconds.sh

#!/usr/bin/env bash

SLEEP_SECOND=7
iter=0;

PARAM="s:h"

MUTEX=${HOME}/.run-x-seconds

LOGFILE=${HOME}/run-logfile

function  usage {
    echo "USAGE: $0 [OPTION] ";
    echo "-s: specify sleep seconds (default ${SLEEP_SECOND})"

    exit 0;
}

while getopts $PARAM opt; do
    case $opt in
        s)
            echo "-s option was supplied. OPTARG: $OPTARG" >&2
            SLEEP_SECOND=$OPTARG;
            ;;
        h)
            usage;
             ;;
    esac
done

## avoid over wrapping
function check_mutex {
    if [ -f ~/${MUTEX} ];then
        echo "mutex file exist!" >&2
        exit 1;
    fi
}

## implement your task
function some_task {
    check_mutex
    echo $(date "+%Y-%m-%d %H:%M:%S") >> ${LOGFILE};
}

echo $BASHPID > ${MUTEX}

for i in $(seq -s " " 1 ${SLEEP_SECOND} 60);do
    some_task &
    sleep ${SLEEP_SECOND};
done

rm -f ${MUTEX}