Add auto complete to your ssh, put into your .bash_profile

Mac SSH Autocomplete

_complete_ssh_hosts ()
{
        COMPREPLY=()
        cur="${COMP_WORDS[COMP_CWORD]}"
        comp_ssh_hosts=`cat ~/.ssh/known_hosts | \
                        cut -f 1 -d ' ' | \
                        sed -e s/,.*//g | \
                        grep -v ^# | \
                        uniq | \
                        grep -v "\[" ;
                cat ~/.ssh/config | \
                        grep "^Host " | \
                        awk '{print $2}'
                `
        COMPREPLY=( $(compgen -W "${comp_ssh_hosts}" -- $cur))
        return 0
}
complete -F _complete_ssh_hosts ssh

I came back for a reminder when setting up a new machine 👍

Thanx from my MacBook :) 👍

Hello,
I did not have a ~/.ssh/config file so I got an error. So I modified the script a little to redirect errors from 'cat'.

_complete_ssh_hosts ()
{
    COMPREPLY=()
    cur="${COMP_WORDS[COMP_CWORD]}"
    comp_ssh_hosts=`cat ~/.ssh/known_hosts 2>/dev/null | \
                    cut -f 1 -d ' ' | \
                    sed -e s/,.*//g | \
                    grep -v ^# | \
                    uniq | \
                    grep -v "\[" ;
                    cat ~/.ssh/config 2>/dev/null | \
                    grep "^Host " | \
                    awk '{print $2}'
                    `
    COMPREPLY=( $(compgen -W "${comp_ssh_hosts}" -- $cur))
    return 0
}
complete -F _complete_ssh_hosts ssh

Great!

i was getting some color fomatting chars in the output off ssh config. It turns out it was due to the colors emitted by "grep".
Probably to make this more robust the --color=never flag can be added to grep

_complete_ssh_hosts ()
{
        COMPREPLY=()
        cur="${COMP_WORDS[COMP_CWORD]}"
        comp_ssh_hosts=`cat ~/.ssh/known_hosts | \
                        cut -f 1 -d ' ' | \
                         sed -e s/,.*//g | \
                         grep -v ^# | \
                         uniq | \
                         grep -v "\[" ;
                         cat ~/.ssh/config | \
                         grep --color=never "^Host " | \
                         awk '{print $2}'
                   `
        COMPREPLY=( $(compgen -W "${comp_ssh_hosts}" -- $cur))
        return 0
}
complete -F _complete_ssh_hosts ssh

It doesn't work for me, I get ~/.zprofile: command not found: complete

It doesn't work for me, I get ~/.zprofile: command not found: complete

The same. MacOS Monterey 12.5.1

Thanks for this script.

I removed the known_hosts section because I want only the .ssh/config file to be parsed.

_complete_ssh_hosts ()
{
        COMPREPLY=()
        cur="${COMP_WORDS[COMP_CWORD]}"
        comp_ssh_hosts=`cat ~/.ssh/config | \
                         grep --color=never "^Host " | \
                         awk '{print $2}'
                   `
        COMPREPLY=( $(compgen -W "${comp_ssh_hosts}" -- $cur))
        return 0
}
complete -F _complete_ssh_hosts ssh

It doesn't work for me, I get ~/.zprofile: command not found: complete

The same. MacOS Monterey 12.5.1

The script is written in bash. zsh has a different way of doing things.

Converted the searches to AWK so there is only 2 commands being called instead of 9 and it is easy to comment out one of the sources if you don't like it.

_complete_ssh_hosts ()
{
        COMPREPLY=()
        cur="${COMP_WORDS[COMP_CWORD]}"
        comp_ssh_hosts=`
            awk '{split($1,aliases,","); if (aliases[1] !~ /^\[/) print aliases[1]}' ~/.ssh/known_hosts ;
            awk '/^Host/ && $2 !~ /[*]/ {print $2}' ~/.ssh/config ;
            `
        COMPREPLY=( $(compgen -W "${comp_ssh_hosts}" -- $cur))
        return 0
}
complete -F _complete_ssh_hosts ssh

Actually, this can work for zsh as well, we just need to enable bash style autocomplete before using this function.
Here is complete example: put this inside ~/.zshrc

#### initialize completion system ####
# see https://unix.stackexchange.com/questions/593433/bash-like-autocompletion-for-ssh-command-in-zsh-shell-with-etc-hosts-file
# see https://zsh.sourceforge.io/Doc/Release/Completion-System.html
autoload -Uz compinit; compinit


# enable bash style autocomplete (requires compinit to be called before this)
# see https://stackoverflow.com/questions/3249432/can-a-bash-tab-completion-script-be-used-in-zsh
# see https://zsh.sourceforge.io/Doc/Release/Completion-System.html
autoload -Uz bashcompinit; bashcompinit


# replace the default ssh autocomplete that comes from compinit 
# with this _complete_ssh_hosts function which looks for hosts in ~/.ssh/config and ~/.ssh/known_hosts
# Note: requires bashcompinit to enable this bash style autocomplete function
# see https://stackoverflow.com/questions/52438964/mac-autocomplete-for-ssh-hosts-in-terminal
# see https://gist.github.com/aliang/1024466
_complete_ssh_hosts ()
{
        COMPREPLY=()
        cur="${COMP_WORDS[COMP_CWORD]}"
        comp_ssh_hosts=`
            awk '{split($1,aliases,","); if (aliases[1] !~ /^\[/) print aliases[1]}' ~/.ssh/known_hosts ;
            awk '/^Host/ && $2 !~ /[*]/ {print $2}' ~/.ssh/config ;
            `
        COMPREPLY=( $(compgen -W "${comp_ssh_hosts}" -- $cur))
        return 0
}
complete -F _complete_ssh_hosts ssh

Thanks!!!

I tweaked it to work when you have multiple known_hosts files, and multiple config files:

# shellcheck shell=bash

# Add tab completion for SSH hostnames
#
# Based on this gist: https://gist.github.com/aliang/1024466
#
# Search in:
#  - ~/.ssh/config
#  - ~/.ssh/config.d/*config
#  - ~/.ssh/*known_hosts

_complete_ssh_hosts ()
{
  COMPREPLY=()
  cur="${COMP_WORDS[COMP_CWORD]}"
  comp_ssh_hosts=$(
    sort -u < <(
      awk '{split($1,aliases,","); if (aliases[1] !~ /^\[/) print aliases[1]}' < <(
        # list all known_hosts files, ignoring blank lines and comments
        # awk code taken from https://stackoverflow.com/a/17396799
        awk '!/^ *#/ && NF' < <(cat ~/.ssh/*known_hosts)
      )
      awk '/^Host/ && $2 !~ /[*]/ {print $2}' <(
        cat ~/.ssh/{config,config.d/*config}
      )
    )
  )
  COMPREPLY=( $(compgen -W "$comp_ssh_hosts" -- $cur) )
  return 0
}
complete -F _complete_ssh_hosts ssh