How to remove trailing whitespaces for multiple files?

Question

Are there any tools / UNIX single liners which would remove trailing whitespaces for multiple files in-place.

E.g. one that could be used in the conjunction with find.

Answer 1

You want

sed --in-place 's/[[:space:]]\+$//' file 

That will delete all POSIX standard defined whitespace characters, including vertical tab and form feed. Also, it will only do a replacement if the trailing whitespace actually exists, unlike the other answers that use the zero or more matcher (*).

--in-place is simply the long form of -i. I prefer to use the long form in scripts because it tends to be more illustrative of what the flag actually does.

It can be easily integrated with find like so:

find . -type f -name '*.txt' -exec sed --in-place 's/[[:space:]]\+$//' {} \+ 

If you're on a Mac

As pointed out in the comments, the above doesn't work if you don't have gnu tools installed. If that's the case, you can use the following:

find . -iname '*.txt' -type f -exec sed -i '' 's/[[:space:]]\{1,\}$//' {} \+ 

Answer 2

Unlike other solutions which all require GNU sed, this one should work on any Unix system implementing POSIX standard commands.

find . -type f -name "*.txt" -exec sh -c 'for i;do sed 's/[[:space:]]*$//' "$i">/tmp/.$$ && mv /tmp/.$$ "$i";done' arg0 {} + 

Edit: this slightly modified version preserves the files permissions:

find . -type f -name "*.txt" -exec sh -c 'for i;do sed 's/[[:space:]]*$//' "$i">/tmp/.$$ && cat /tmp/.$$ > "$i";done' arg0 {} +