How do I properly quote this bash pipeline for watch?

Question

I\'ve built up this pipeline:

echo \"scale=2;$(cat io | grep wchar | awk \'{print $2}\')/(1024^3)\" | bc

Now I\'m trying to watch

Answer 1

Try having watch invoke the shell:

watch sh -c 'echo "scale=2;$(awk '/wchar/ {print $2}' io)/(1024^3)" | bc'

This is similar to having it invoke a script but without needing a separate file.

Answer 2

The problem is about the single quotes for awk, you could fix it by escaping single quotes.

watch 'echo "scale=2;$(cat io | grep wchar | awk '"'"'{print $2}'"'"')/(1024^3)" | bc'

It is all about how to escaping single quotes inside single quotes, there is a good explanation "BASH, escaping single-quotes inside of single-quoted strings"