How to convert Windows end of line in Unix end of line (CR/LF to LF)

There should be a program called dos2unix that will fix line endings for you. If it's not already on your Linux box, it should be available via the package manager.

sed cannot match \n because the trailing newline is removed before the line is put into the pattern space, but it can match \r, so you can convert \r\n (DOS) to \n (Unix) by removing \r:

sed -i 's/\r//g' file

Warning: this will change the original file

However, you cannot change from Unix EOL to DOS or old Mac (\r) by this. More readings here:

How can I replace a newline (\n) using sed?

Actually, Vim does allow what you're looking for. Enter Vim, and type the following commands:

:args **/*.java
:argdo set ff=unix | update | next

The first of these commands sets the argument list to every file matching **/*.java, which is all Java files, recursively. The second of these commands does the following to each file in the argument list, in turn:

• Sets the line-endings to Unix style (you already know this)
• Writes the file out iff it's been changed
• Proceeds to the next file

I'll take a little exception to jichao's answer. You can actually do everything he just talked about fairly easily. Instead of looking for a \n, just look for carriage return at the end of the line.

sed -i 's/\r$//' "${FILE_NAME}"

To change from Unix back to DOS, simply look for the last character on the line and add a form feed to it. (I'll add -r to make this easier with grep regular expressions.)

sed -ri 's/(.)$/\1\r/' "${FILE_NAME}"

Theoretically, the file could be changed to Mac style by adding code to the last example that also appends the next line of input to the first line until all lines have been processed. I won't try to make that example here, though.

Warning: -i changes the actual file. If you want a backup to be made, add a string of characters after -i. This will move the existing file to a file with the same name with your characters added to the end.

Update: The Unix to DOS conversion can be simplified and made more efficient by not bothering to look for the last character. This also allows us to not require using -r for it to work:

sed -i 's/$/\r/' "${FILE_NAME}"

The tr command can also do this:

tr -d '\15\32' < winfile.txt > unixfile.txt

and should be available to you.

You'll need to run tr from within a script, since it cannot work with file names. For example, create a file myscript.sh:

#!/bin/bash

for f in `find -iname \*.java`; do
    echo "$f"
    tr -d '\15\32' < "$f" > "$f.tr"
    mv "$f.tr" "$f"
    recode CP1252...UTF-8 "$f"
done

Running myscript.sh would process all the java files in the current directory and its subdirectories.