What should I do to run a script on specific time without cron?

Question

I want to run a script without using cron at specific time. But it is not working.

#!/bin/sh

DATE=`date | cut -d' ' -f4`

#Date is getting printed, if I run it manually, without any error. But file is not created at scheduled time.

echo $DATE

if [[ $DATE == "07:06:55" ]]
then
echo "this is a test program" >> xyz.log

fi

Solution 1

If you want to run it only once, you can use the at command : https://en.wikipedia.org/wiki/At_(command)

Example :

echo "echo \"this is a test program\" >> /tmp/xyz.log" | at 1127 apr 11

If you want to run it every day, you might need to use a loop :

#!/bin/bash

while true;
do
    DATE=`date | cut -d' ' -f4`
    echo $DATE
    if [[ $DATE == "11:33:00" ]]
    then
            echo "this is a test program" >> xyz.log
            sleep 1s
    fi
done

Solution 2

You can use at:

at -f "$script" 'now + 24 hours' &>/dev/null

The at command explained with an example

I found this also:

watch -n <the time> <your command or program or executable>

The watch command on the web

Comments

[αғsнιη]

this askubuntu.com/q/844533/283843 can help you?

[muru]

If you want to run it daily, please explain why you can't use cron.

[Kusalananda]

cron is the correct service to use for running a a command daily at a specific time. If not using cron, you will have to arrange for the script to re-execute itself at a particular time in the future, maybe using at (which is part of cron), or by sleeping (which would make the executions drift over time), and you would additionally have to set up an initial execution of the script at reboots (again, this is easy to do with cron, or with some other system service).

[Roushan Jha]

#!/bin/sh echo "this is a test program" >> xyz.log | at 0745 It didn't work, since I want to run it daily.

[Joji Antony]

OK, I have updated the answer

[Silas Cheeseman]

at still uses the cron facility.