I liked your use of ed. You can avoid one pipe with the -s option: `echo ,n | ed -s file`. Also, another POSIX one-process option besides awk: `pr -tn file` (wi

I liked your use of ed. You can avoid one pipe with the -s option: `echo ,n | ed -s file`. Also, another POSIX one-process option besides awk: `pr -tn file` (with different padding).