How to set up a cron job to run an executable every hour?
CLinuxGccCronCrontabC Problem Overview
I need to set up a cron job that runs an executable compiled using gcc once every hour.
I logged in as root and typed crontab -e
Then I entered the following and saved the file.
0 * * * * /path_to_executable
However, the cron job does not work.
I see that when I type /...path_to_executable I get a segmentation fault.
I can only execute the executable from the folder it is located in.
Is there a way I can solve this problem?
C Solutions
Solution 1 - C
0 * * * * cd folder_containing_exe && ./exe_name
should work unless there is something else that needs to be setup for the program to run.
Solution 2 - C
The solution to solve this is to find out why you're getting the segmentation fault, and fix that.
Solution 3 - C
You can also use @hourly instant of 0 * * * *
Solution 4 - C
If you're using Ubuntu, you can put a shell script in one of these directories: /etc/cron.daily, /etc/cron.hourly, /etc/cron.monthly or /etc/cron.weekly.
For more detail, check out this post: https://askubuntu.com/questions/2368/how-do-i-set-up-a-cron-job
Solution 5 - C
Did you mean the executable fails to run , if invoked from any other directory? This is rather a bug on the executable. One potential reason could be the executable requires some shared libraires from the installed folder. You may check environment variable LD_LIBRARY_PATH
Solution 6 - C
use
path_to_exe >> log_file
to see the output of your command also errors can be redirected with
path_to_exe &> log_file
also you can use
crontab -l
to check if your edits were saved.
Solution 7 - C
Since I could not run the C executable that way, I wrote a simple shell script that does the following
cd /..path_to_shell_script
./c_executable_name
In the cron jobs list, I call the shell script.