Saturday, August 28, 2010

Process list with /proc -r

You may already have encountered this small issue, you are on a system and want to list processes but /proc has no read permission so you cannot list entries. Does it stop us? No, obviously we can iterate all possible pids and check for /proc/<pid>/ directory.

In shell we can get a simple process list with:
$ for P in $(seq 1 32168); do
  [ -d "/proc/$P" ] || continue
  echo "$P: $(cat /proc/$P/cmdline 2>/dev/null |sed 's/\x00/ /g')"
1: init [2]
1423: -bash
But what if we want more information, just like ps from procps gives us?