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

[Rick Matthews]

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?

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.

Thanks in advance!

Rick