topic Re: crontab job and run on shell in Operating System - Linux

crontab job and run on shell

hangyu — Tue, 13 Feb 2007 20:45:24 GMT

I hv a crontab job (script) that can be run normally , now I try to run it on the shell but can't be run ( I sure I don't have any typing mistake as I copy the statement from the crontab ) , can advise what is difference between run a script on crontab and manually ? thx

Re: crontab job and run on shell

Stuart Browne — Wed, 14 Feb 2007 00:59:43 GMT

Environment.

The cron environment has nowhere near the PATH and other shell environment available to it.

So if you rely upon a shell-based environment variable or 'alias', these need to be put into the shell script you're running from cron.

Also note, that you *MUST HAVE* the hash-bang ('#!/bin/bash') at the start (along with executable permissions), otherwise cron won't know how it executes.

Re: crontab job and run on shell

hangyu — Wed, 14 Feb 2007 03:43:58 GMT

thx reply,

I still have a bit misunderstand , do you mean I need to add ('#!/bin/bash') at the beginning of my script ? if not that , can advise what I need to do ? thx

Re: crontab job and run on shell

Ivan Ferreira — Wed, 14 Feb 2007 08:21:29 GMT

What is the error that you get? Ensure that a line was not divided in two during the copy/paste operation.

Re: crontab job and run on shell

Wilfred Chau_1 — Wed, 14 Feb 2007 15:08:30 GMT

agree. environment is the issue.
also please add the path of the command to the PATH environment variable. Like PATH=$PATH:/usr/lcoal/bin

or use full path for all the commands in the script.

Re: crontab job and run on shell

Ivan Ferreira — Wed, 14 Feb 2007 15:15:12 GMT

Remember that the problem is not as usual. The problem is that the script works in cron but does not work in the shell.

Re: crontab job and run on shell

James R. Ferguson — Wed, 14 Feb 2007 17:45:15 GMT

Hi:

As noted, the environment in which a 'crontask' runs is sparse. Instead of adding the environmental variables you commonly need (e.g. PATH, etc.) to every script that you 'cron', source (read) a file that you define specifically to hold environmental variables.

Thus, your scripts would begin something like this:

# cat ./myscript
#!/bin/bash
. /home/hangyu/config
echo "hello ${WHO}"
exit 0

# cat ./config
WHO=Hangyu

Then run:

# ./myscript

...Now you have defined *one* configuation file that you can modify for *all* your scripts' needs.

Regards!

...JRF...