Variable in crontab

18Googol2 · 03-05-2009, 01:01 AM

Assume my username is foo, and I wanna set up PATH variable in my crontab. I specify $USER for portable purpose:

PATH="/bin:/sbin:/usr/bin:/usr/sbin:/home/$USER/bin"

But cron doesnt inteprete $USER as foo :S

Then I have no choice but to hard code my username: /home/foo/bin :S

Is there any way to "not" hard code my username? Thanks.

w3bd3vil · 03-05-2009, 01:58 AM

A workaround would be to create a bash script and put that in the crontab instead.
I don't think you can define variables in crontab as Bash.

colucix · 03-05-2009, 03:25 AM

The variable providing the username of the crontab's owner is LOGNAME, not USER. Here is a relevant excerpt from man 5 crontab:

Quote:

Several environment variables are set up automatically by the cron(8) daemon. SHELL is set to
/bin/sh, and LOGNAME and HOME are set from the /etc/passwd line of the crontab´s owner. HOME and
SHELL may be overridden by settings in the crontab; LOGNAME may not.

18Googol2 · 03-05-2009, 09:57 AM

Quote:

Originally Posted by colucix

The variable providing the username of the crontab's owner is LOGNAME, not USER. Here is a relevant excerpt from man 5 crontab:

$LOGNAME is exactly what Im after. Thanks

18Googol2 · 03-05-2009, 10:13 AM

No, it doesnt work. cron doesnt intepretes $HOME and $LOGNAME as I wish. I let it echo $PATH and here is the output:

/bin:/sbin:/usr/bin:/usr/sbin:/usr/local/bin:/usr/local/sbin:/$HOME/bin

colucix · 03-05-2009, 11:00 AM

You're right. If using

Code:

PATH=/bin:/usr/bin:$LOGNAME/bin
5 * * * * echo $PATH > cron.log

it does not work, since there is no variable substitution in crontab. But if you set it using export in the crontab entry it should work:

Code:

5 * * * * export PATH=/bin:/usr/bin:/home/$LOGNAME/bin ; echo $PATH > cron.log

However, the most convenient way is to put your commands in a shell script and use the proper sha-bang to force the execution of the script as if the shell was invoked as a login shell

Code:

#!/bin/bash -l

in this way the bash profile is sourced and the PATH is set the way you have in your usual shell environment.