How to remove trailing whitespaces for multiple files?

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,\}$//' {} \+

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 {} +

I've been using this to fix whitespace:

while IFS= read -r -d '' -u 9do    if [[ "$(file -bs --mime-type -- "$REPLY")" = text/* ]]    then        sed -i -e 's/[ \t]\+\(\r\?\)$/\1/;$a\' -- "$REPLY"    else        echo "Skipping $REPLY" >&2    fidone 9< <(find . \( -type d -regex '^.*/\.\(git\|svn\|hg\)$' -prune -false \) -o -type f -print0)

Features:

• Keeps carriage returns (unlike [:space:]), so it works fine on Windows/DOS-style files.
• Only worries about "normal" whitespace - If you have vertical tabs or such in your files it's probably intentional (test code or raw data).
• Skips the .git and .svn VCS directories.
• Only modifies files which file thinks is a text file.
• Reports all paths which were skipped.
• Works with any filename.