Can awk print lines that do not have a pattern?

Question

Can awk print all lines that did not match one of the patterns?

In other words, I want to transform some lines but leave the rest unchanged. So, if a /pattern/ matched I would provide a custom block to print the line. I just need to provide a default matcher (like an else) to print the other lines.

Answer 1

You can negate the pattern to get else like behavior:

awk '
    /pattern/ {
        # custom block to print the line    
    }
    !/pattern/ {
        # else do other things
    }
'

Answer 2

Yes, just use any non-zero number and awk will do its default thing which is to print the line:

awk '7' file

If you want it as an "else", put "next" after whatever lines you select for special processing so this one isn't executed for them too.

awk '/pattern/{special processing; next} 7' file