We have 10 PC with some version of Ubuntu and only remote access. While doing some upgrades to custom software I did not notice that the line endings in some scripts were Windows version (CR+LF) and not the Unix version (LF). So now when I want to launch the script it gives an error:

bash: /usr/local/bin/portsee: /usr/bin/python^M: bad interpreter: No such file or directory

Is there a way to change all line endings in a script from terminal. The thing is that I can not install any new software to this group of PC-s.

  • 1
    Use the sed command from the duplicate's accepted answer.
    – terdon
    Jul 26, 2016 at 15:07

2 Answers 2


Option 1: dos2unix

You can use the program dos2unix, which is specifically designed for this:

dos2unix file.txt

will replace all CR from all lines, in place operation.

To save the output in a different file:

dos2unix -n file.txt output.txt

You might need to install it first by:

sudo apt-get install dos2unix

Option 2: sed

Or you can use sed to replace all CR (\r) from line endings:

sed -i.bak 's/\r$//' file.txt

With option -i, the file will be edited in-place, and the original file will be backed up as file.txt.bak.

  • 3
    dos2unix and unix2dos are present in cygwin as well
    – Pallav Jha
    Jul 23, 2019 at 9:00
  • 2
    This answer shows applying dos2unix recursively. Useful when moving a git repo from windows to ubuntu. Aug 3, 2020 at 8:11
  • 3
    sed worked for me but had to supply the global flag as in: sed -i.bak 's/\r$//g' file.txt
    – Jono
    Nov 2, 2020 at 17:58
  • If anyone else gets an illegal byte sequence error when using the sed command, just add this one the same line before the sed command: LC_ALL=C sed ...
    – Nate
    Nov 8, 2021 at 22:12

The sed solution is not portable to all platforms. It didn't work for me on macOS unless I did brew install gsed and used gsed 's/\r$//'.

For a solution that works in most places without installing anything, I use

tr -d '\r'

To edit a file in-place, I produce the new data in a subshell before erasing and overwriting the original file:

echo "$(tr -d '\r' < file)" > file
  • Sponge from moreutils is a nice utility for reading and writing in the same line as well: tr -d '\r' <file | sponge file. It writes to memory until STDOUT finishes, then writes the contents to the file.
    – David
    Oct 27, 2021 at 12:02
  • Useful if you have sponge installed, but it's not installed by default on macOS. May 13, 2022 at 20:12

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