Question

I need to use the output of a command as a search pattern in sed. I will make an example using echo, but assume that can be a more complicated command:

echo "some pattern" | xargs sed -i 's/{}/replacement/g' file.txt

That command doesn’t work because “some pattern” has a whitespace, but I think that clearly illustrate my problem.

How can I make that command work?

Thanks in advance,

Answer 1

Use command substitution instead, so your example would look like:

sed -i "s/$(echo "some pattern")/replacement/g" file.txt

The double quotes allow for the command substitution to work while preventing spaces from being split.