How to convert newlines in a set of files?

Question

I have set of files with either Windows newlines (CRLF) or Unix newlines (LF).

How can I convert all newlines in all files to Mac newlines (CR)?

Answer 1

The question doesn't explicitly say, but I assume you mean text files, and need to convert the line delimiter format? OS X doesn't ship with command-line file converter tools, you have to build them yourself. Perl is good for Q&D utilities like this:

perl -pe 'if (s/\r?\n/\r/g) {$f=1}; if ($f&&eof()) {s/\r\z//}' PCfile.txt >Macfile.txt

or, to convert in place:

perl -pe 'if (s/\r?\n/\r/g) {$f=1}; if ($f&&eof()) {s/\r\z//}' -i convertfile.txt

Note: this script is a little more complicated than it probably needs to be, because it's written to work on on both PC-format (CRLF line terminators) and unix files (LF terminators), and leave files that're already in the old traditional MacOS format (CR separators between lines) alone. Also, the PC and unix formats put a terminator after the last line, while Mac format doesn't (it uses line separators, not terminators), so this script detects when it's actually translating, and removes the last delimiter.

Answer 2

CR line endings were mostly used in Mac OS 9 and earlier. OS X uses LF line endings in most places.

Some of the methods below add a newline to the end of files that don't already end with a newline. Some don't work on Windows or if the default line endings are not LF.

CRLF to LF:

dos2unix *.txt
sed -i '' $'s/\r//' *.txt
tr -d '\r'

LF to CRLF:

unix2dos *.txt
recode ../crlf *.txt

LF to CR:

unix2mac *.txt
awk 'BEGIN{ORS="\r"};1'
tr '\n' '\r'

CR to LF:

mac2unix *.txt
awk 'BEGIN{RS="\r"};1'

CRLF or CR to LF:

ruby -e 'print gets(nil).gsub /\r\n?/,"\n"'
ruby -i -pe 'BEGIN{$/="\r"};$_=$_.sub("\n","").sub("\r","\n")' *

CRLF or LF to CR:

ruby -i -ne 'print $_.chomp+"\r"' *.txt