How To Autocomplete SSH Hosts

So you know about SSH config file, there are several awesome articles on the subject:

This awesome article

and this one that covers some tips and tricks

SSH Config Tips and Tricks

Daniel McCarney ・ Feb 1 '19

#linux #cli #ssh #security

Now, with all of that, you still have to remember the full host entry to connect and it will not be autocompleted for you.

let's say I have the following in my config file:

Host unicorn-one
  HostName 1.2.3.4
  User amusallam
  IdentityFile ~/.ssh/id_rsa

Host unicorn-two
  HostName 2.2.3.4
  User amusallam
  IdentityFile ~/.ssh/id_rsa

Host unicorn-three
  HostName 3.2.3.4
  User amusallam
  IdentityFile ~/.ssh/id_rsa

and now I type ssh unicorn into terminal and hit ⇥ Tab, it will not auto complete...

But fear not! for I have what your heart desires!

Autocomplete Script

I've only tried this on MacOs.

courtesy of this stackexchange answer:

answer re: Autocomplete server names for SSH and SCP

Jan 28 '15

105

Found it!!

It seems that in Ubuntu the entries in ~/.ssh/known_hosts are hashed, so SSH completion cannot read them. This is a feature, not a bug. Even by adding HashKnownHosts no to ~/.ssh/config and /etc/ssh/ssh_config I was unable to prevent the host hashing.

However, the hosts that I am…

Open Full Answer

add the following file: /etc/bash_completion.d/ssh whose contents:

_ssh() 
{
    local cur prev opts
    COMPREPLY=()
    cur="${COMP_WORDS[COMP_CWORD]}"
    prev="${COMP_WORDS[COMP_CWORD-1]}"
    opts=$(grep '^Host' ~/.ssh/config ~/.ssh/config.d/* 2>/dev/null | grep -v '[?*]' | cut -d ' ' -f 2-)

    COMPREPLY=( $(compgen -W "$opts" -- ${cur}) )
    return 0
}
complete -F _ssh ssh

Then load that file: in your ~/.bash_profile, add:

## load ssh autocompletion
. /etc/bash_completion.d/ssh

and reload by running source ~/.bash_profile or just terminate your terminal and reopen it.

and voila!

(The flashes you see below are me hitting ⇥ Tab)

easy peasy!

Extra helpful alias

if you want to see a list of all your hosts, you can add this alias to your .bash_profile:

# list all "Host" and "HostName" lines, then remove the strings: "Host " and "HostName "
alias sshhosts="grep -w -i -E 'Host|HostName' ~/.ssh/config | sed 's/Host //' | sed 's/HostName //'"

reload by running source ~/.bash_profile or just terminate your terminal and reopen it.

then you can run it:

sshhosts

from unicorn example above, this prints:

unicorn-one
  1.2.3.4
unicorn-two
  2.2.3.4
unicorn-three
  3.2.3.4