Shell Programming and Scripting

NR won't work in this case, though. NR will increment for every line regardless of whether a PORT substituion occured. The "substitution" counter needs to be something independent of NR (j in my version).

On an unrelated note, since gsub returns the number of substitutions made, we can further reduce the code to:

Code:

awk 'gsub(/PORT/,i){i+=!(++j%n)}1' i=1 n=2 file

Like the earlier versions of this approach, it treats multiple substitutions on a single line as one. That's probably a bug. Though if we can be certain that only one instance of PORT will occur on a line, then it's fine, and as a bonus we can reduce by one more character:

Code:

awk 'sub(/PORT/,i){i+=!(++j%n)}1' i=1 n=2 file

And that concludes this episode of OCD AWKing. Thank you for tuning in.

Cheers,
Alister

Oh my bad you're right, I was using the example file of post #10 of TonyFullerMalv

Very nice!

The following correctly handles multiple instances of "PORT" on a single line:

Code:

awk '{while (sub(/PORT/,i)) i+=!(++j%n)}1' i=1 n=1 data

Finally, we can put this one to bed.
Alister