How to show all processes in Erlang?

registered() is returning all the processes, but the shell is truncating output.

you can print the result to see everything:

io:format("~p~n", [registered()]).

> rp(registered()). Documentation here

As long as your are in shell you can use regs():

1> regs().

** Registered procs on node nonode@nohost **
Name                  Pid          Initial Call                      Reds Msgs
application_controlle <0.33.0>     erlang:apply/2                   65717    0
code_server           <0.38.0>     erlang:apply/2                  592348    0
disk_log_server       <0.129.0>    disk_log_server:init/1             323    0
disk_log_sup          <0.128.0>    supervisor:disk_log_sup/1          367    0
dtls_connection_sup   <0.70.0>     supervisor:dtls_connectio           84    0
dtls_udp_sup          <0.71.0>     supervisor:dtls_udp_sup/1           81    0
erl_prim_loader       <0.6.0>      erlang:apply/2                24923843    0
erl_signal_server     <0.46.0>     gen_event:init_it/6                 51    0
...

** Registered ports on node nonode@nohost **
Name                  Id              Command
ok

I believe the easiest way is:

> io:write(registered()).