Re^4: Clever Padding (chomp, Win32)

Yeah, it used to say a whole lot more than that. I hope all of perlport (a link to perldoc which appears to be down) hasn't been whittled down to a single sentence. That would surely be less misleading but also clearly much less useful.

- tye

Comment on Re^4: Clever Padding (chomp, Win32)

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Re^5: Clever Padding (chomp, Win32) by ikegami (Patriarch) on Jan 27, 2010 at 23:49 UTC
It does say more about line endings (including <<but when accessing a file in "text" mode, STDIO translates it to (or from) "\015\012">>), but that's all it says about `chomp`. In most operating systems, lines in files are terminated by newlines. Just what is used as a newline may vary from OS to OS. Unix traditionally uses "\012", one type of DOSish I/O uses "\015\012", and Mac OS uses "\015". Perl uses "\n" to represent the "logical" newline, where what is logical may depend on the platform in use. In MacPerl, "\n" always means "\015". In DOSish perls, "\n" usually means "\012", but when accessing a file in "text" mode, STDIO translates it to (or from) "\015\012", depending on whether you’re reading or writing. Unix does the same thing on ttys in canonical mode. "\015\012" is commonly referred to as CRLF. To trim trailing newlines from text lines use chomp(). With default settings that function looks for a trailing "\n" character and thus trims in a portable way. When dealing with binary files (or text files in binary mode) be sure to explicitly set $/ to the appropriate value for your file format before using chomp(). Then it goes on talking about \012 vs \n. I agree that it could use a major rewrite, but I don't see anything that comes close to implying `chomp` removes two chars.	[reply] [d/l] [select]

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Re^5: Clever Padding (chomp, Win32)
by ikegami (Patriarch) on Jan 27, 2010 at 23:49 UTC

chomp

In most operating systems, lines in files are terminated by newlines. Just what is used as a newline may vary from OS to OS. Unix traditionally uses "\012", one type of DOSish I/O uses "\015\012", and Mac OS uses "\015".
Perl uses "\n" to represent the "logical" newline, where what is logical may depend on the platform in use. In MacPerl, "\n" always means "\015". In DOSish perls, "\n" usually means "\012", but when accessing a file in "text" mode, STDIO translates it to (or from) "\015\012", depending on whether you’re reading or writing. Unix does the same thing on ttys in canonical mode. "\015\012" is commonly referred to as CRLF.
To trim trailing newlines from text lines use chomp(). With default settings that function looks for a trailing "\n" character and thus trims in a portable way.
When dealing with binary files (or text files in binary mode) be sure to explicitly set $/ to the appropriate value for your file format before using chomp().

Then it goes on talking about \012 vs \n.

I agree that it could use a major rewrite, but I don't see anything that comes close to implying chomp removes two chars.

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