u2d

u2d [file...]

file...
    One or more file names to convert from Unix to DOS format. If no files are specified, reads from standard input.

The `u2d` command converts text files from Unix format to DOS format. Specifically, it replaces Unix-style line endings (LF - Line Feed, `\n`) with DOS-style line endings (CRLF - Carriage Return Line Feed, `\r\n`). This is useful when you need to transfer text files created or modified on a Unix-like system to a DOS or Windows system, as these operating systems traditionally use CRLF for line breaks.

It processes files in-place, overwriting the original file with the converted version. This is important to note as it modifies the existing file. The tool provides a basic conversion but isn't as robust as other utilities which handle character encoding issues or different end of file encodings.

Consider using more robust tools like `dos2unix` and `iconv` for advanced conversions.

The command overwrites the original files. It does not handle character encoding conversions. Be sure to back up files before conversion if needed. If reading from standard input, you'll need to redirect the output to a file if you want to save it.

If no files are specified as command-line arguments, `u2d` reads from standard input. This is useful when you want to pipe the output of another command through `u2d` to convert it before writing it to a file.

The error handling in `u2d` is basic. It typically reports file errors, but might not provide detailed diagnostics. It's advisable to check the file permissions and ensure there's enough disk space before running the command. Check exit codes from the command to confirm success.

The `u2d` command (along with its counterpart `d2u`) likely originated as a simple utility for transferring text files between Unix-like systems and DOS/Windows systems in the early days of cross-platform computing. As DOS/Windows adopted a different line-ending convention, simple tools were needed to resolve the incompatibility. While `u2d` addresses the line-ending issue, more robust tools like `dos2unix` and `unix2dos` gained popularity due to features like encoding detection and conversion.

d2u(1), dos2unix(1), unix2dos(1), iconv(1)