Run a command every X seconds. Differs from `watch` because it does not clear the screen at each command run

watchloop

#!/bin/bash

# NOTE: This requires GNU getopt.  On Mac OS X and FreeBSD, you have to install this
# separately; see below.
OPTS=`getopt -o hn: --long help,interval: -n 'parse-options' -- "$@"`

if [ $? != 0 ] ; then echo "Failed parsing options." >&2 ; exit 1 ; fi

# echo "$OPTS"

# Note the quotes around `$OPTS': they are essential!
eval set -- "$OPTS"

want_help=false
interval=10
while true; do
  case "$1" in
    -h | --help ) want_help=true; shift ;;
    -n | --interval ) interval="$2"; shift; shift ;;
    -- ) shift; break ;;
    * ) break ;;
  esac
done

if test "${want_help}" == "true"; then
    echo "Usage: [-n|--interval <interval>] [-h]"
    echo "    -h|--help:     print help"
    echo "    -n|--interval: sleep interval in seconds"
    exit 0
fi

if test "$interval" -le 1; then
    echo "invalid interval=$interval"
    exit -1
fi



###
#   DO THE WORK
###

while true; do
    echo
    date
    "$@"
    sleep $interval
done