Fastest & Most Core way to replace "\r\n" with "\n" in a file?

Question

I suppose tr is a more core method and thus probably a faster way to replace things within a given file.

However tr can only replace equal amounts of characters. meaning...

2 characters can only be replaced with 2 characters which means replacing

\r\n with \n is out of the question via tr

is the next best option sed ?

is sed the most core and fastest way to replacing \r\n with \n in a file given the lack of capabilities in tr ?

would like an example if possible.

Answer 1

With sed, you can do:

sed 's/\r$//'

The same way can do with tr, you only have to remove \r:

tr -d '\r'

although this will remove all instances of \r, not necessary followed by \n.

Answer 2

OR use dos2unix

for example:

$ echo -ne "1\r\n2" |  od -A n -t x1
 31 0d 0a 32
$ echo -ne "1\r\n2" | dos2unix | od -A n -t x1
 31 0a 32

we can see replace \r\n with \n