Using regex with `rename` version from `util-linux`

Question

I’m using a GNU/Linux distribution where the utility rename comes from util-linux and I want to make full use of regular (Perl or POSIX) expression

Answer 1

The following command gives the expected result with your input file but using the perl version:

rename 's/foo_\D+(\d+)/foo_$1/' *.ext

You can test the command using -n option to rename