[Linux-disciples] Subtitutions of all permutations

[Stephen R Laniel]

A Perl puzzler for y'all; maybe it's not as difficult as I seem to think
it is:

Suppose you have an HTML tag like the img tag that looks like so:

<img alt="blah" width="blah" src="foo" height="gern" style="geh" />

You want to strip out everything except for the "alt" and the "src", but
they could appear anywhere in the list of attributes. So in Perl

s{<img(.*)alt=(".*") src=(".*")(.*)(/?)>}{<img src=$2 alt=$1 />}g;

would work, but then you'd have to do another version of the same
substitution where the src came first and the alt came second, right?

In greater generality, I guess what I'm wondering is whether there's any
way to say "If there's any permutation of [list of things], perform this
substitution on it." Is there any way to do that?

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