unix2dos - Linux


The unix2dos command is used to convert text files from Unix/Linux line endings (LF) to DOS/Windows line endings (CRLF). This is useful in environments where files are shared between Unix/Linux and Windows systems, ensuring correct file formatting and preventing issues in applications that expect specific end-of-line markers.


The basic syntax of unix2dos is as follows:

unix2dos [options] [file...]

If no file is specified, unix2dos reads from the standard input and writes to the standard output. Multiple files can be processed in a single unix2dos command.


  • -c MODE: Convert using the specified mode. The modes include ascii, 7bit, iso, mac with the default being ascii.
  • -k: Keep the original file’s date and time.
  • -n : Convert oldfile to newfile without altering the original file.
  • -o: Overwrite the original file with the converted content.
  • -q: Operate quietly, suppressing any warnings.
  • -s: Skip binary files (files that contain non-text data).


  1. Convert a single file and overwrite it:
    unix2dos myfile.txt
  2. Convert multiple files without overwriting them:
    unix2dos -n original1.txt new1.txt
    unix2dos -n original2.txt new2.txt
  3. Convert input from standard input and send to standard output:
    echo "This is a test" | unix2dos

Common Issues

  • Binary file conversion: Accidentally running unix2dos on a binary file may corrupt it. Use the -s option to skip binary files.
  • File permissions: Lack of sufficient permissions might result in an inability to modify files. Ensure you have the necessary permissions or use sudo if needed.
  • Overwriting files: If the -o option is mistakenly used, the original files are overwritten, which might be undesirable. Always backup important files.


unix2dos can be combined with other commands for powerful scripting applications. For example, to change line endings in text files found using find:

find . -name "*.txt" -exec unix2dos {} \;

Or in a batch process combined with grep to selectively convert files containing a specific pattern:

grep -lR "pattern" /path | xargs unix2dos
  • dos2unix: Converts files the other way round—from DOS line endings to Unix.
  • sed, awk: These tools can also manipulate line endings in advanced scripting scenarios.

For further details and understanding, the official unix2dos documentation can be a valuable resource along with community forums and tech blogs dedicated to Unix and Linux systems.