Comment by teo_zero

In POSIX world you aren't encouraged to use a specific command for each goal you might have. Instead you get a set of basic tools and combine them to achieve the desired result. Without system() you wouldn't have pipes, and you would need one command for every task you might want to run.

Point in case I encountered this week: I was editing a list and wanted to remove duplicates without changing the order of the lines. There's no ready-made program to do that, but this sequence of piped command served the purpose:

  cat -n | sort -uk 2 | sort | cut -f 2-

Fortunately my text editor supports system().