Home / ubuntu / Questions / 313033
Accepted
mini
Asked: 2013-06-27 09:31:58 +0800 CST

How can I see/stop current running crontab tasks?

  • 772
  1. How can I see crontab tasks which are in progress?
  2. How can I stop crontab tasks which are in progress, manually?

Is [this] question about see the current running cron processes?

Yes

To kill a process manually one way is to use pkill

I had thought about pkill/killall, but some of my commands in crontab file are respectively! it means that after finishing a command, the next one will be started! for example:

sudo crontab -e
00 10 * * * /usr/bin/wget LINK ; shutdown -h now

So, If I kill wget, the computer will be powered off!!! -> I want to kill a cron task fully, not a part of it!

The next pkill problem: What about scripts? (I've imported some bash scripts to crontab -e) --> sudo pkill ???

cron

3 Answers

  1. Best Answer

    Firstly, use only one command per line in crontab. Change this crontab line:

    00 10 * * * /usr/bin/wget LINK ; shutdown -h now

    so it looks like:

    00 10 * * * /path/to/my/crontab/script1.sh

    and create /path/to/my/crontab/script1.sh with this content:

    #!/bin/bash
/usr/bin/wget LINK
shutdown -h now

    Of course, don't forget to give it execution permission:

    chmod +x /path/to/my/crontab/script1.sh

    Secondly, you can see running crontab tasks, in a useful and readable format, in the output of:

    ps -o pid,sess,cmd afx | egrep -A20 "( |/)cron( -f)?$"

    They will appear in the first lines, something like this:

    1108  1108 cron
4288  1108 \_ CRON
4289  4289     \_ /bin/sh -c /path/to/my/crontab/script1.sh
4290  4289         \_ /bin/bash /path/to/my/crontab/script1.sh
4295  4289             \_ /usr/bin/wget LINK

    First column is PID, second is Session ID and third is the command started by cron. You can kill all the processes related to a specific cron task using the Session ID, so in the example above you should kill Session ID 4289:

    pkill -s 4289
    • 51

  2. To kill a process manually one way is to use pkill. pkill will stop all processes that have the following pattern in its name. for example to stop all wget processes use:

    sudo pkill wget
    • 0

  3. change your cronjob like this

    00 10 * * * /usr/bin/wget LINK && shutdown -h now

    This should work, because the && means that the second command only gets executed, when the first one was finished correctly (returning status 0 to the console/system), which shouldn't be the case (because the process got killed by the user and it should return another value then 0).

    • 0