[kw-pm] $1 matching question

[Daniel R. Allen]

I've got a regex question that I'm probably just being stupid about:

bash% echo -e "9 \n \n 2" | perl -ne'/(\d+)/; print "$1 ";'

has the following result:

9 9 2

Shouldn't it be '9  2' ?  And the result is the same with:

bash% echo -e "9 \n \n 2" | perl -ne'$z = ""; /(\d+)/; $z = $1; print "$z
" if $z;'

Which means $1 is actively being assigned to, when there isn't a match!

deparse tells me:

bash% perl -MO=Deparse -ne'/(\d+)/; print "$1 ";'
LINE: while (defined($_ = <ARGV>)) {
    /(\d+)/;
    print "$1 ";
}

...which looks just like I'd expect.  Maybe I just took a stupid pill this
morning.


-Daniel

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