Using /m when $ is followed by punctuation

jrw has asked for the wisdom of the Perl Monks concerning the following question:

Seeking wisdom for a regexp like s/(^...$\n)+//m which seeks to delete all three-character interior lines. My actual regexp is different, but it has the sequence $\n in it, which perl interprets as $\ n rather than $ \n. I can trick it by adding /x and then interposing a space between $ and \n, but I'd rather not. I wish there were a \z variation that meant "match an interior newline" when used with /m.

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Re: Using /m when $ is followed by punctuation by ikegami (Patriarch) on Aug 05, 2014 at 22:40 UTC
Drop the useless `$`. `/ $ \n /xm` [download] is the same as just `/ \n /xm` [download]	[reply] [d/l] [select]
Re^2: Using /m when $ is followed by punctuation by jrw (Monk) on Aug 05, 2014 at 22:46 UTC
Thanks, I see that now. Do you know of an answer to the general question: how to get perl to parse `$` followed by by an escape sequence as `$` `\whatever` rather than `$\` `whatever`?	[reply] [d/l] [select]
Re^3: Using /m when $ is followed by punctuation by ikegami (Patriarch) on Aug 05, 2014 at 22:48 UTC
I don't think you'd ever need to do that, but I can think of a couple of solutions: `(?x: $ )` `(?=\n\|\z)` (if `/m` is in effect) `(?=\n?\z)` (if `/m` isn't in effect) `(?![^\n])` (if `/m` isn't in effect)	[reply] [d/l] [select]
Re^4: Using /m when $ is followed by punctuation by jrw (Monk) on Aug 05, 2014 at 23:03 UTC