how to use xargs with sed in search pattern

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          


        

Answer 1

You need to tell xargs what to replace with the -I switch - it doesn't seem to know about the {} automatically, at least in some versions.

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