Cron environment variables

Question

I'm running a simple shell script that runs just fine in a login shell from cron, where it doesn't run. For some reason, /usr/local/bin is not on the users path when run from cron while it is when run in a shell.

Where is the environment for cron determined?

Answer 1

Generally, from the non-login environment established for /bin/sh, which is the default used to run the command.

You can set additional environment variables in your crontab in most versions, vis:

PATH=/usr/local/bin:/usr/bin:/bin
@reboot whatever

Check crontab(5) for details; man 5 crontab

Answer 2

Check which shell your script is using.

The shell and variables for crontab are specified in /etc/crontab

x@x:~$ cat /etc/crontab 

SHELL=/bin/sh
PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin

The profile file used by sh is in user home.

x@x:~$ ls ~/.profile 
/home/x/.profile

You can add PATH variable in end of this file (Make sure you are adding in profile file of correct user)

PATH="$PATH:/usr/local/bin"

or you can add the same line in your own script.