Sick Unix Trick #347 ... ghost files.

# Open the file, creating it
open $fh, '+>', 'foo.txt';

# Immediately unlink the file ... it will remain
# until you close the filehandle, then disappear
unlink 'foo.txt';

# Put something in it to test
print $fh "Foo\n";

# Rewind to the start of the temp file
seek $fh, 0, 0;

# Read it back in and see what you have
$in = <$fh>;
print "Read: $in\n";

# You don't even *have* to remember to close it,
# but it is a good habit ...
close $fh;
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Updated: Note that unlike File::Temp, this trick will clean up after itself no matter what happens to the process. It does not depend upon DESTROY being invoked.

By unix rules, the system normally should not remove anything from /tmp while running. In /tmp any program is supposed to be able to create files, write to them, and assume that files placed there will remain until removed by the owner. A program can not assume that the contents of /tmp will survive a reboot. That makes startup scripts the place for the system to do /tmp cleanup.

Some admins put in place some other policy they dream up, but the unix police will someday get 'em.

Putting /tmp on its own spindle, or at least a large partition, and mounting with the sticky bit set fixes most problems that non-unix policies are meant to solve. Going all BOFH on programs which don't clean up after themselves takes care of the rest.

Of course, users may clean up their own messes any time they like.

File::Temp is a useful way to create tempfiles, but you'll still have to figure out how to get them cleaned up.

Also, it's best if you can clean them up yourself, and only leave them lying around in the rare case that your program crashes. Things like END blocks are useful places for this sort of cleanup.

Actually, File::Temp will clean up after you if you want it to.

Yes indeed, I didn't know that! Very handy. Not entirely foolproof, for example if your process crashes perl or is killed with SIGKILL, but probably close enough for most purposes.

About cleaning them up myself.. I am creating some modules, and i have distribution in mind. I only trust people downloading and configuring so far- installing a module, and setting up a cron, may be too much to expect from some people.

Then just let them configure where temp files go, defaulting to /tmp, try your best to clean them up when you exit, and document that some systems won't automatically clean that area, and on the rare occasion something goes Very Wrong, the user may need to clean it manually once in awhile, or set up a cronjob to do it automatically. That's really all you can do.

Of course there are plenty of Unix/Linux monks here...

In which case, we prefer you to use the Chatterbox to ask quick questions.