grep does not work in crontab script

blizunt7 · 08-24-2007, 09:59 AM

Hey all,
I have a script that does a grep for a file in a directory.
Following is just idea of what Im doing.

Code:

#!/bin/bash

cd /home/user
grep -l sometext *

When i schedule this in crontab grep does not find the text, however if I simple run this from the command line, grep finds the text just fine. So I thought i was an environment issue. Then on the top of the script I added and exported ALL env variables of my current shell, then scheduled the script again, but still nothing.

Is there something funny about running grep in a scheduled script?

Thanks all!

MensaWater · 08-24-2007, 10:25 AM

When you run a script from command line it inherits your environment including the PATH variable that tells it where to find commands.

When you run in cron it gets minimal environment. When you start the script it executes bash (due to the interpreter line) and may lose even that minimal environment.

Therefore it is important you include the environment within the script itself.

So type "which grep" to find out where grep is:
which grep
/bin/grep

Then in your script either set the PATH variable to include that directory (/bin in the above) OR just use the fully qualified path to the grep command.
e.g.

Either

Code:

#!/bin/bash

PATH=/bin
cd /home/user
grep -l sometext *

Or

Code:

#!/bin/bash

cd /home/user
/bin/grep -l sometext *

You don't have to worry about "cd" because it is built into bash itself.

blizunt7 · 08-24-2007, 10:37 AM

From Command line:

Code:

$ which grep
/bin/grep

within Script (as cronjob)

Code:

+ env
SHELL=/bin/sh
OLDPWD=/home/vcs
USER=vcs
PATH=/usr/bin:/bin
PWD=/home/vcs/log/vvcs
HOME=/home/vcs
SHLVL=1
LOGNAME=vcs
_=/usr/bin/env

+ which grep
/bin/grep

So i dont think the location of the grep command is my issue.
This is just weird.

MensaWater · 08-24-2007, 01:16 PM

Have you tried:

Code:

#!/bin/bash

cd /home/user
grep -l sometext *  2>&1 | tee >/tmp/script.log

So it will send stderr to stdout then add both to /tmp/script.log to see what if any errors it may be spawning? The cronlog itself only records the success or failure of scheduling - not the actual output if any that the script may have generated.

Also have you verified the user running the cron is the same as owns the files you're trying to grep from (and /home/user)? It might be a simple permissions issue.

blizunt7 · 08-24-2007, 01:43 PM

Yes, when i am scheduling the job in crontab, I output to log, and issue 2>&1. I see that the grep does in-fact find all the files in the directory (as to indicate i am in the correct directory), but the grep returns nothing. And all permissions are set to allow owner and other rwx. I am the owner, and I am issuing the crontab job.

Im about to give up, and see about another route to solve my issue.
I wish you could help, and I appreciate it!!, I feel like I just cant get you the information you need to assist me.

MensaWater · 08-24-2007, 02:19 PM

Quote:

I see that the grep does in-fact find all the files in the directory (as to indicate i am in the correct directory), but the grep returns nothing

That sentence suggests what the issue is.

The "-l" flag of grep specifically returns ONLY the file name - not the line that matched.

From the grep man page:

Quote:

-l, --files-with-matches
Suppress normal output; instead print the name of each input
file from which output would normally have been printed. The
scanning will stop on the first match.

It sounds as if you want the text rather than the file name - if so just do the "grep sometext *" (i.e. without the -l flag).

If you need BOTH the file name AND the matching text you could do something like:

Code:

for FILE in `grep -l sometext *`
do echo $FILE
   grep sometext $FILE
   echo ""
done

The first grep -l gets you the list of files. Then the loop will print each file name and below it the text that matched from the file listed. The echo "" is just to insert a line between each file and its output for legibility.