11/4    Ok, I rtfm'd and stfw'd. How in perl do I swap 'foo' with 'bar' and
        'bar' with 'foo'? I assume it has to be one s///g statement, but how?
        \_ let the "I can do this in .... notes" olympics begin!
           I'll start.  I think you want:
                perl -pi -e `s/foo/bar` filename
           \_ I wonder if perl is a good candidate for upperbounding kolmogorov
              complexity of various text processing programs.
           \_ I think he wants to swap them.  Not just simple replace.  There's
              probably a more elegant way, but easiest is to use three replaces:
                s/foo/%%placeholder%%/g
                s/bar/foo/g
                s/%%placeholder%%/bar/g
              If it's a complex match, you'll probably want to do grouping,
              and will need some temp variables to save grouping matches across
              s/// statements, --scotsman
              \_ Ah ok. Thx. I was thinking there was some magical perl
                 operator that would do this for me in one statement.
                 \_ s/foo|bar/{foo=>'bar',bar=>'foo'}->{$&}/ge
                    --dbushong
                    \_ niloc's shortened solution:
                       s/foo|bar/$& eq'foo'?'bar':'foo'/ge
                       -geordan
                       \_ Wow, look at all that wasted white space... :-)
                       \_ Neat. Thx again.
                       \_ slight tweak:
                          s/foo|bar/$&gt c?bar:foo/ge
                          -alexf
                          \_ Works only on the "foo/bar" case, but I
                             appreciate the sentiment.  It also gives
                             bareword warnings, I think. -geordan
                             \_ Not in the raw perl -pe context on soda;
                                it'll (naturally) start screaming bloody
                                murder once it's using -w or something like
                                that. A hack's a hack =) -alexf