Nope; the extension is OPTIONAL.

http://perldoc.perl.org/perlrun.html:

The extension, if supplied (emphasis added), is used to....

And though this is already discussed (below), the examples (in the 5.12 doc) of using -p, -i and -e together are constructed this way:

perl -pi -e ...
except where the -p is separated by a space from a -i (and I didn't find an explicit explanation of that, either).

In reply to Re^2: Perl pie with $1 replacements ? by ww
in thread Perl pie with $1 replacements ? by Plankton

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