skinp skinp - 2 months ago 26
Linux Question

Removing created temp files in unexpected bash exit

I am creating temporary files from a bash script. I am deleting them at the end of the processing, but since the script is running for quite a long time, if I kill it or simply CTRL-C during the run, the temp files are not deleted.

Is there a way I can catch those events and clean-up the files before the execution ends?

Also, is there some kind of best practice for the naming and location of those temp files?

I'm currently not sure between using:

TMP1=`mktemp -p /tmp`
TMP2=`mktemp -p /tmp`
...


and

TMP1=/tmp/`basename $0`1.$$
TMP2=/tmp/`basename $0`2.$$
...


Or maybe is there some better solutions?

Answer

You could set a "trap" to execute on exit or on a control-c to clean up.

trap "{ rm -f $LOCKFILE }" EXIT

Alternatively, one of my favourite unix-isms is to open a file, and then delete it while you still have it open. The file stays on the file system and you can read and write it, but as soon as your program exits, the file goes away. Not sure how you'd do that in bash, though.

BTW: One argument I'll give in favour of mktemp instead of using your own solution: if the user anticipates your program is going to create huge temporary files, he might want set "TMPDIR" to somewhere bigger, like /var/tmp. mktemp recognizes that, your hand-rolled solution (second option) doesn't. I frequently use "TMPDIR=/var/tmp gvim -d foo bar", for instance.