Realisation of a "Crontab" with Bash

frenchn00b · 11-02-2011, 02:48 AM

Hi,

There is a bash script that is launched every 1 minutes, and I plan to use it for various things for multimedia.

I wanna have HH:MM and eventually the day that if matches or superior, then activate (run) given bash script.

If PC is turned off, then it should forget it and skip.

Would you have some ideas how it could be made. With locks?

$HOME/.bashcrontab would contain the ini file (as crontab -e)

thanks

Nominal Animal · 11-02-2011, 04:35 AM

Is there a reason why you don't use at for this? You are almost certainly already running the atd daemon which provides exactly this as a service. See man 1 at for details.

frenchn00b · 11-02-2011, 10:31 AM

Quote:

Originally Posted by Nominal Animal

Is there a reason why you don't use at for this? You are almost certainly already running the atd daemon which provides exactly this as a service. See man 1 at for details.

yes:
from bash script, how could you add a line? simple answer

not possible, nor working:

Code:

 echo "0 7,11  *       *       *       cd ;  sh script.sh" < crontab -e

Nominal Animal · 11-02-2011, 11:18 AM

Quote:

Originally Posted by frenchn00b

from bash script, how could you add a line? simple answer

I'm sorry, I don't understand the question. What do you mean by line?

Here is an example:

Code:

echo "(date ; ls -laF /tmp ) > /tmp/example.log" | at -t 201111022359

will run date ; ls -laF /tmp and redirect the output to /tmp/example.log on 2011-11-02 23:59:00 (Wed Nov 2 23:59:00), local time.

Quote:

Originally Posted by frenchn00b

not possible, nor working:

As the crontab manpage instructs, the proper form of your command is

Code:

( crontab -l ; echo "0 7,11  *       *       *       cd && sh -c script.sh" ) | crontab -

Note also the small change in the command: It reads change to the home directory, and if that succeeds, run script.sh. The right side of && is only run if the left side succeeded.