Optimize shell script for multiple sed replacements

Question

I have a file containing a list of replacement pairs (about 100 of them) which are used by sed to replace strings in files.

The pairs go like:

Answer 1

You can cut down unnecessary awk invocations and use BASH to break name-value pairs:

while IFS='|' read -r old new; do
   # echo "$old :: $new"
   sed -i "s~$old~$new~g" file
done < replacement_list

IFS='|' will give enable read to populate name-value in 2 different shell variables old and new.

This is assuming ~ is not present in your name-value pairs. If that is not the case then feel free to use an alternate sed delimiter.