- Most people who write shell scripts really don't want to write a 'ps' or 'ip' (or for non-Linux, 'ifconfig') replacement. On the other hand, Python and Ruby have libraries that talk to /proc and the network ioctls directly.

- most shell script authors don't even use bash arrays, and higher level data types don't exist. It's hard to represent a C struct in shell. C libraries are therefore exposed to shell scripts by scraping their stdout.