Their first example is bad:

    ps aux | grep nginx | grep root | grep -v grep

can be done instead (from memory, not at a Linux machine ATM):

    ps -u root -C nginx

which is arguably better than their solution:

    psc 'process.name == "nginx" && process.user == "root"'

▲ xorcist 13 hours ago | parent | next [-]

The commands in their example are not equivalent. The ps | grep thing searches the full command line including argument while ps -C (and, presumably, the psc thing) just returns the process name.

Should you for some reason want to do the former, this is easiest done using:

  pgrep -u root -f nginx

which exists on almost all platforms, with the notable exception of AIX.

Their other slightly convoluted example is:

  psc 'socket.state == established && socket.dstPort == uint(443)'

which is much more succinct with:

  lsof -i :443 -s TCP:ESTABLISHED

	▲	dundarious 9 hours ago \| parent \| next [-]
		It has process.cmdline as well as .name
	▲	wang_li 10 hours ago \| parent \| prev [-]
		Many new tools appear because people don't know how to use the existing tools or they think the existing tool is too complicated. In time the new tool becomes just as, or more, complicated than the old tool. Because there is a reason the old tool is complicated, which is that the problem requires complexity.

▲ mxey 9 hours ago | parent | prev [-]

“ss” also has filters, no need for grep

ss -o state established '( dport = :ssh or sport = :ssh )'