How to remove trailing whitespaces with sed?

Question

I have a simple shell script that removes trailing whitespace from a file. Is there any way to make this script more compact (without creating a temporary file)?

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Answer 1

Thanks to codaddict for suggesting the -i option.

The following command solves the problem on Snow Leopard

sed -i '' -e's/[ \t]*$//' "$1"

Answer 2

At least on Mountain Lion, Viktor's answer will also remove the character 't' when it is at the end of a line. The following fixes that issue:

sed -i '' -e's/[[:space:]]*$//' "$1"

Answer 3

For those who look for efficiency (many files to process, or huge files), using the + repetition operator instead of * makes the command more than twice faster.

With GNU sed:

sed -Ei 's/[ \t]+$//' "$1"
sed -i 's/[ \t]\+$//' "$1"   # The same without extended regex

I also quickly benchmarked something else: using [ \t] instead of [[:space:]] also significantly speeds up the process (GNU sed v4.4):

sed -Ei 's/[ \t]+$//' "$1"

real    0m0,335s
user    0m0,133s
sys 0m0,193s

sed -Ei 's/[[:space:]]+$//' "$1"

real    0m0,838s
user    0m0,630s
sys 0m0,207s

sed -Ei 's/[ \t]*$//' "$1"

real    0m0,882s
user    0m0,657s
sys 0m0,227s

sed -Ei 's/[[:space:]]*$//' "$1"

real    0m1,711s
user    0m1,423s
sys 0m0,283s

Answer 4

To only strip whitespaces (in my case spaces and tabs) from lines with at least one non-whitespace character (this way empty indented lines are not touched):

sed -i -r 's/([^ \t]+)[ \t]+$/\1/' "$file"