crontab ifconfig problem

Question

/home/myname/bin/script:

#!/bin/bash
ifconfig > /home/myname/foo

Crontab:

* * * * * /home/myname/bin/script

...waits 1 minute...

@@ 11:35:51 [myname@comp - ~]$ ls foo
-rw-r--r-- 1 myname myname 0 Jul  7 11:35 foo
@@ 11:35:55 [myname@comp - ~]$

I can't figure out why foo would end up empty. Running the ipconfig command on the command line works exactly as you'd expect, dumping its output into a file just like normal. For reference, I'm running Ubuntu 8.04.

Answer 1

try using the full path to the ifconfig executable in your script.

whereis ifconfig will give you the path.

I don't know what ipconfig does in ubuntu. :)

Answer 2

In a cron job you probably want to redirect both stdout and stderr to the file. Change your script to this:

#!/bin/bash
ifconfig &> /home/myname/foo

and you'll see the error message in your output file.

See All About Redirection in the Bash Programming How To for more info.

Answer 3

1. You probably need the full path to ipconfig in your script, or did you mean ifconfig? Either way, you should use the full path.
2. You capture stdout in /home/myname/foo, but not stderr which probably gets the clue that you're missing here. Check your email for the output of the cronjob.

Answer 4

have you tried manually running your script?

cd in to /home/myname/bin/

./script

does it make the foo with contents as expected?

is the script executable?

I know that might sound like simple things but sometimes that is what is overlooked, especially when I make a script