How to run the shell script periodically without using Crontab?

Question

I do not have previlage to use crontab -e to run my script. Is there other way to periodically run my script? Basically I need to run it once a week.

Answer 1

If you can't/don't want to keep a terminal open, you could run it in GNU Screen/tmux or with nohup.

Examples:

screen sh -c 'while sleep 7d; do mycommand; done'

or

tmux 'while sleep 7d; do mycommand; done'

Note: these commands will run mycommand the first time after a week and then periodically, not directly. Change according to preference.

See the projects' documentation for more info on attaching/detaching sessions.

(7d is GNU specific, I believe. Just put 604800 there instead if the sleep version only supports seconds.)

Answer 2

If enabled and installed, you can use the at command. However it is a one time only scheduling....you'd have to run a new at command within the thing that you wanted rescheduling.

Check out the man pages for help on the at command.

But remember, it is not always installed/enabled on all Linux/UNIX systems.

Answer 3

The REAL answer to this is to contact your friendly neighborhood systems administrator, explain your problem, and ask them to enable cron access for you. You should explain how your program runs, its resource requirements, and generally make a promise that you will not harm the system if you get cron access privs.

Answer 4

Another approach would be to have a cronjob running on a different machine, that uses ssh to execute a certain command on the target server. If you set up key based login, this will be easy.

Just set up a cronjob on another machine that looks like e.g.

0 0 * * 7   /usr/bin/ssh remoteuser@remotehost mycommand

With the exception of the remote server being offline at the execution time, this would be reliable over remote server restarts and other things.