Print a comma except on the last line in Awk

Question

I have the following script

awk \'{printf \"%s\", $1\"-\"$2\", \"}\' $a >> positions;

where $a stores the name of the fi

Answer 1

Single pass approach:

cat "$a" | # look, I can use this in a pipeline! 
  awk 'NR > 1 { printf(", ") } { printf("%s-%s", $1, $2) }'

Note that I've also simplified the string formatting.