Anyone can find those features in the man page. I guarantee that the number of people who use those features is much larger than the number of people who read

Anyone can find those features in the man page. I guarantee that the number of people who use those features is much larger than the number of people who read the source before today. The UNIX style promoted in the "cat -v Considered Harmful" paper may have made sense at one time, but it doesn't make sense anymore. For example: It seems that UNIX has become the victim of cancerous growth at the hands of organizations such as UCB. 4.2BSD is an order of magnitude larger than Version 5, but, Pike claims, not ten times better. This logic gives the same consideration to people who are digging in the source code for these utilities as to people who actually use them. When you consider the relative numbers, that's a very elitist attitude (for some value of "elite"). Also consider the explanation given in another comment for why "cat -n" is unnecessary: If you want to number a file's lines, 'echo ,n | ed file | sed 1d' or 'awk ''{ print NR " " $0 }''' will do just fine. Munging text like that is a pretty common skill for Unix users, but by no means universal. If the man page for cat is pretty simple and readable, and the feature doesn't bloat the code to the point of causing maintenance problems, and there's somebody who's willing to write the code, then enabling "cat -n" a win for users.