T o n g wrote: > The following shell script will work: > > -------------------------- > #!/bin/sh > sleep $1 > beep > ------------------------- > > name it 'alarm' and 'alarm 30' will alarm you after 30 seconds.
That works if you know how many seconds to wait. Let's say that it is Mon, 17 Jan 2011 12:08:08 -0700 and you want an alarm to trigger at 3pm local time at Mon, 17 Jan 2011 15:00:00 -0700. Then you know that you can sleep for 10312 seconds. alarm-sleep 10312 That is great. But calculating that value when you are sleepy isn't for everyone. Instead I would program that into the script to do for you. Use GNU date's --date extension to calculate the date from a given date string. until="3pm" now=$(date +%s) then=$(date -d "$until" +%s) delay=$(( $then - $now )) sleep $delay Then you can say something like: sleep-until-do 3pm some command with args here Below is a script I call sleep-until-do which sleeps until the given time and then invokes the given command. I use it to turn on the radio to listen to the news at the top of the hour. Perhaps you will find it useful too. Bob #!/bin/sh # Copyright 2009, 2010, 2011 Bob Proulx <b...@proulx.com> # You may freely use, modify and/or distribute this file. if [ $# -lt 1 ]; then echo "Error: Missing time argument" 1>&2 exit 1 fi if [ $# -lt 2 ]; then echo "Error: Missing do-command argument" 1>&2 exit 1 fi until=$1 shift echo "Info: $until interpreted as:" $(date -R -d "$until") now=$(date +%s) then=$(date -d "$until" +%s) delay=$(( $then - $now )) if [ $delay -gt 2 ]; then echo Sleeping $delay seconds... sleep $delay else echo Info: Time has passed. fi echo Invoking: "$@" exec "$@"
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