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dearN
Asked: 2012-04-02 10:52:21 +0800 CST

Script doesn't run via crontab but works fine standalone

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I have a script that reminds me to restart my computer if uptime is more than, say 3 days (although its set to 0 days now just to check if the script is running as my computer has been up only over a day..).

I realize it isn't the most elegant script but I am trying! :) 

#!/bin/bash

up=$(uptime | grep "day" > /home/username/uptime.foo && awk < /home/username/uptime.foo '{ print $3 }')

[[ $up -gt 0 ]] && xmessage -center "Restart!"

I have made it executable by chmod + x checkup.sh and it works fine when I run it fro the terminal via ./checkup.sh

My crontab entry for this script is:

46 14 * * * /home/username/Desktop/./checkup.sh

So it runs at 14:46hrs daily...

So... I am thinking it should run, unless I didn't something really silly. Also, do you think it's ok to move this bash script to /bin?

cron

3 Answers

  1. Best Answer

    One thing at a time:

    First let's give you a user based bin folder:

    cd ~/ && mkdir bin

    You want to use crontab. Let's start with something really simple: 

    * * * * * touch /tmp/testing.txt

    Okay, so that works

    Now let's try running a script that does the same 

    * * * * * /home/username/bin/touchtest.sh

    to run once a minute until you get it working
    No you don't need a ./ in the middle of the line. ./ is for when you are giving relative urls.
    Okay, so that works

    Now let's try running a script that calls xmessage 

    * * * * * /home/username/bin/rebootwarn.sh

    not working

    First we need to not depend on environment variables. This includes path setting, x11 settings, or anything else(python and ruby environment variables come to mind...)

    Let's make ours look a bit like anacron's proper cron file..I saved this as test

    #Borrowed from anacron
SHELL=/bin/sh
PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin
#End borrowed from anacron

* * * * *   /bin/bash /home/username/bin/test.sh

    Set to run once a minute

    crontab test to import it

    On to the script

    #!/bin/bash
PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin
export DISPLAY=:0.0
up=$(uptime | grep "day" > /home/dnaneet/uptime.foo && awk < /home/dnaneet/uptime.foo '{ print $3 }')

[[ $up -gt 0 ]] && xmessage -center "Restart!"`

    Okay, so that works...what did we do?
    We changed all the commands not to depend on paths we didn't explicitly set
    We ran our script explicitly with bash
    We told the script that we expect to be on DISPLAY :0.0

    • 83

  2. The problem was solved read the manual in Google:

    description:

    1. I have script using #!/bin/bash as header
    2. I put the script on /home/wc3/palert/

    analysis:

    1. crontab can't run my script
    2. But if I run manually it show the output and also I can see the result on my web
    3. It means crontab can't get the environment not like when you run your script on your script folder

    answer:

    1. put your environment using this line below on your script with: 

      PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/home/wc3/palert

      change this: /home/wc3/palert
      with: the place that you put your script e.g. /home/budi/script.sh

    sample:

    #!/bin/bash
PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/home/budi
# Script continues...

    Try put your script on crontab.

    • 20

  3. In my case all was cause it is not loaded profile on a first place. So just use -l or --login. Like so @reboot bash -l /path/to/scirpt.sh >> /tmp/some.log

    • 1