Nuno J. Silva wrote: > In a BASH script I'm writing, I need temporary files. Unfortunately, not > only some of the used programs don't accept stdin nor stdout, but they > also require "extensions" on the input/output file.
Yep. A common problem. > As I want to be sure nothing is overwritten, I tried calling mktemp with > a modified template: > > $ mktemp tmp.XXXXXXXXXX.ext > mktemp: too few X's in template `tmp.XXXXXXXXXX.ext' Beware that different mktemp implementations behave different. Some implementations will not produce an error but since the X's are not on the right the filename produced will not be unique. $ mktemp /tmp/tmp.XXXXXXXXXX.ext /tmp/tmp.XXXXXXXXXX.ext $ ls -ldog /tmp/tmp.XXXXXXXXXX.ext -rw------- 1 0 2010-03-22 17:50 /tmp/tmp.XXXXXXXXXX.ext $ mktemp /tmp/tmp.XXXXXXXXXX.ext ...blocks trying to create a unique file... Not what you want. > Is this a limitation of mktemp (X's must be on the right)? Yes. It is a legacy limitation. As Jim mentioned a feature for this was recently added to GNU coreutils. The traditional way to handle this problem was to create a temporary directory and then create files with suffixes inside the directory. Because the directory is uniquely named you can use a known name for the file within the directory. This is off of the top of my head, untested, I am not responsible for any problems with it, and may contain a mistake and so forth but you might try something like this example. This is a do-nothing but with enough to hopefully show you the technique. #!/bin/sh unset tmpdir trap 'cd / ; rm -rf $tmpdir' EXIT tmpdir=$(mktemp -d) || exit 1 cd $tmpdir || exit 1 echo foo > file1.ext sed 's/foo/bar/' file1.ext > file2.ext cat file2.ext ls -log exit 0 Bob
