Unexpected Awk results with sh -c

Question

I am trying to sudo a command that uses Awk, and it looks like awk works differently inside sh -c.

echo '1 2' | awk '{print $2}'

2

sh -c "echo '1 2' | awk '{print $2}'"

1 2

Why is this happening?

Answer 1

You use double quotes, therefore $2 is evaluated. The inner single quotes don't affect this anymore. If $2 is empty, you are basically calling awk '{print }'. Consequently, you get the whole input line as output.

You could for example escape the $ with a backslash: \$2