> except the first one spawns an extra process for no reason.

I wonder how many processes I could spin up in the time it would take for me to figure out "hmm, no, invoking that command would use one more process than necessary..."

I don't give a hoot about that stuff when I'm doing stuff interactively. e.g. when using `more`.

In my opinion it's better to replace `cat FOO | more` with `< FOO more`, because cat is used because people first think that they want to take contents of some file and pass it through some filter.

I didn't know you could put the redirection first. You learn something new every day. Maybe that form would make it more mnemonic for some people, because it more resembles a pipeline.

BTW, the authors effectively embraced having the functionality of using `cat` instead of < .

> The use of cat to feed a single input file to a program has to some degree superseded the shell’s < operator, which illustrates that general-purpose constructs - like cat and pipes - are often more natural than convenient special-purpose ones.

If you're going to write shell scripts or do anything sophisticated with the shell, it's worth understanding the difference. And there is a fundamental difference. With |, standard input is hooked up to a pipe. With <, standard input is hooked up directly to the file. Sometimes it does matter.

The purpose cat serves is that it lets you forget about < until you really need it.

The comparison was between cat + pipe and < ...