Why does `htop` show more process than `ps`

Question

In ps xf

26395 pts/78   Ss     0:00  \_ bash
27016 pts/78   Sl+    0:04  |   \_ unicorn_rails master -c config/unicorn.rb                                           
27042 pts/78   Sl+    0:00  |       \_ unicorn_rails worker[0] -c config/unicorn.rb                                        

In htop, it shows up like:

Why does htop show more process than ps?

Answer 1

By default, htop lists each thread of a process separately, while ps doesn't. Turn off the display of threads: in the “Setup / Display options” menu, “Hide userlands threads”. This puts the following line in your ~/.htoprc (you can alternatively put it there manually):

hide_userland_threads=1

(Also hide_kernel_threads=1, but it's 1 by default.)

Answer 2

For me, on a more-or-less current arch linux system, ps xf shows me only the processes owned by my user ID. htop shows me all processes. Try ps -ef for a list of all processes, or perhaps ps -ejH to get a child/parent relationship listing.