There's also a shortcut: the flip-flop operator: 

while (<>) {
    if (1 eq (/foo/ .. (1x0))) {
        do_something();
    }
}

[download]
this will not check for /foo/ once it's found.

Of course, this is not any better than 

my $found;
while (<>) {
    if (!$found && /foo/) {
        $found++;
        do_something()
    }
}

[download]

In reply to Re: Doing "it" only once by ambrus
in thread Doing "it" only once by Limbic~Region

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