How to add a carriage return before every newline?

I have a file that only uses n for new lines, but I need it to have rn for each new line. How can I do this?

For example, I solved it in Vim using :%s/n/rn/g, but I would like to use a script or command-line application. Any suggestions?

I tried looking this up with sed or grep, but I got immediately confused by the escape sequence workarounds (I am a bit green with these commands).

If interested, the application is related to my question/answer here


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Method 1

You can use unix2dos (which found on Debian):

unix2dos file

Note that this implementation won’t insert a CR before every LF, only before those LFs that are not already preceded by one (and only one) CR and will skip binary files (those that contain byte values in the 0x0 -> 0x1f range other than LF, FF, TAB or CR).

or use sed:

CR=$(printf 'r')
sed "s/$/$CR/" file

or use awk:
awk '{printf "%srn", $0}' file

awk -v ORS='rn' 1 file

or use perl:
perl -pe 's|n|rn|' file

Method 2

This is exactly what unix2dos does:

$ unix2dos file.txt

That will replace file.txt in-place with a version with CRLF line endings.

If you want to do it with sed, you can insert a carriage return at the end of every line:

sed -e 's/$/r/' file.txt

This replaces (s) the zero-size area right before the end of the line ($) with r. To do in-place replacement (like unix2dos does), use sed -i.bak, although that is a non-standard extension – if you don’t have it, use a temporary file.

Method 3

If you are doing the conversion on a Unix machine (OS X, Linux), open the file with vi or vim:

$ vim my-file

press the ESC key to ensure that you are not in insert mode, then type
:set ff=dos

:set fileformat=dos

This does conversion in place by setting the file format.

To write the file and quit the editor use


On the command line you can do
$ vi +':w ++ff=dos' +':q' my-file

Method 4

Doing this with POSIX is tricky:

  • POSIX Sed does not support r or 15. Even if it did, the in place
    option -i is not POSIX
  • POSIX Awk does support r and 15, however the -i inplace option
    is not POSIX
  • d2u and dos2unix are not POSIX utilities, but ex is
  • POSIX ex does not support r, 15, n or 12

To remove carriage returns:

awk 'BEGIN{RS="1";ORS="";getline;gsub("r","");print>ARGV[1]}' file

To add carriage returns:

awk 'BEGIN{RS="1";ORS="";getline;gsub("n","r&");print>ARGV[1]}' file

Method 5

A portable shell function that will do this:

u2dos() (set -f; IFS='
'; printf '%srn' $(cat "$1"))

With that you can do:
u2dos file >dosfile

Method 6

In awk you can try

awk '{print $0 "r"}'

awk -v r=$'r' '{print $0 r}'

The $'r' is an example of ANSI-C style quoting as supported by a few shells like ksh93, bash, zsh, mksh and FreeBSD sh and likely to be included in issue 8 of the Single Unix Specification.

It offers a general way to express weird characters, try this, for example:

awk -v r=$'U0001F608' '{print $0 r}'

Method 7

You can use GNU sed command:

 sed -i 's/$/x0D/g' file.txt
  • $ – regex for end of line
  • x0D – hex value for carriage return in ASCII
~] cat -v file.txt  

~] sed -i 's/$/x0D/g' file.txt

~] cat -v file.txt             

All methods was sourced from or, is licensed under cc by-sa 2.5, cc by-sa 3.0 and cc by-sa 4.0

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