Small AWK idiomatic tip. If you want to add a char at the end of each line.EXCEPT the last one. for instance you are generating an array. awk NR>1 {printf(",\n");} {printf($0);} TLDR; The NR stands for number record, the line it is processing usually. the printf statement prints out without the ORS( output record separator) usually newline (\n) char. END;