[NTLUG:Discuss] Why would a command stop working?

[Steve Baker]

Rick Matthews wrote:

> I've heard that there are no stupid questions, but I'm pretty sure this
> one would win an honorable mention...
> 
> I have a script that has been running a couple of times a week for the
> past 6 months or so, without problems. Today I noticed a problem with
> the output and started back-tracking.
> 
> There's a line in the script similar to this:
> 
> cat file1 | sort | uniq > file2
> 
> The problem is that the duplicates are no longer being removed by uniq.
> I created test files and tried it from the command line (as root) and
> still had duplicates in file2.
> 
> I know I must be missing something simple... what is it?

Have you checked sort *and* uniq - it's possible that sort stopped
sorting *or* that uniq stopped uniq'ing...the symptoms would be similar
but it would help to be clear about which of them failed.

I don't see any reason why one or other program would stop doing their
jobs (both are pretty simple programs) - but one thing to check would be:

* Run 'which sort' and 'which uniq' to verify that you havn't somehow
  accidentally put a program with the same name somewhere else in the
  search path.

> File1 has grown to about 3.5 meg. It is a text file with one domain per
> line. I'm running Red Hat 7.1 on a P200 with 128 MB RAM.

But was your test file that large?  Try it with a *really* simple test
file - ten lines say.

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