asterisk
Telephone and exchange (phone) server.
TLDR
[R]econnect to a running server, and turn on logging 3 levels of [v]erbosity
$ asterisk -r -vvv
[R]econnect to a running server, run a single command, and return
$ asterisk -r -x "[command]"
Show chan_SIP clients (phones)
$ asterisk -r -x "sip show peers"
Show active calls and channels
$ asterisk -r -x "core show channels"
Show voicemail mailboxes
$ asterisk -r -x "voicemail show users"
Terminate a channel
$ asterisk -r -x "hangup request [channel_ID]"
Reload chan_SIP configuration
$ asterisk -r -x "sip reload"