By: AJ

AJ — Mon, 17 Nov 2008 03:46:48 +0000
From Ubuntu 7.04+'s /etc/bash_completion:

_known_hosts()
{
       local cur curd ocur user suffix aliases global_kh user_kh hosts i host
       local -a kh khd config

  COMPREPLY=()
  cur=`_get_cword`
  ocur=$cur

  [ "$1" = -a ] || [ "$2" = -a ] && aliases='yes'
  [ "$1" = -c ] || [ "$2" = -c ] && suffix=':'
  [[ $cur == *@* ]] && user=${cur%@*}@ && cur=${cur#*@}
  kh=()

  # ssh config files
  [ -r /etc/ssh/ssh_config ] &&
    config=( "${config[@]}" "/etc/ssh/ssh_config" )
  [ -r "${HOME}/.ssh/config" ] &&
    config=( "${config[@]}" "${HOME}/.ssh/config" )
  [ -r "${HOME}/.ssh2/config" ] &&
    config=( "${config[@]}" "${HOME}/.ssh2/config" )

  if [ ${#config[@]} -gt 0 ]; then
      # expand path (if present) to global known hosts file
      global_kh=$( eval echo $( sed -ne 's/^[ \t]*[Gg][Ll][Oo][Bb][Aa][Ll][Kk][Nn][Oo][Ww][Nn][Hh][Oo][Ss][Tt][Ss][Ff][Ii][Ll][Ee]['"$'\t '"']*\(.*\)$/\1/p' "${config[@]}" ) )
      # expand path (if present) to user known hosts file
      user_kh=$( eval echo $( sed -ne 's/^[ \t]*[Uu][Ss][Ee][Rr][Kk][Nn][Oo][Ww][Nn][Hh][Oo][Ss][Tt][Ss][Ff][Ii][Ll][Ee]['"$'\t '"']*\(.*\)$/\1/p' "${config[@]}" ) )
  fi

  # Global known_hosts files
  [ -r "$global_kh" ] &&
      kh=( "${kh[@]}" "$global_kh" )
  [ -r /etc/ssh/ssh_known_hosts ] &&
      kh=( "${kh[@]}" /etc/ssh/ssh_known_hosts )
  [ -r /etc/ssh/ssh_known_hosts2 ] &&
      kh=( "${kh[@]}" /etc/ssh/ssh_known_hosts2 )
  [ -r /etc/known_hosts ] &&
      kh=( "${kh[@]}" /etc/known_hosts )
  [ -r /etc/known_hosts2 ] &&
      kh=( "${kh[@]}" /etc/known_hosts2 )
  [ -d /etc/ssh2/knownhosts ] &&
      khd=( "${khd[@]}" /etc/ssh2/knownhosts/*pub )

  # User known_hosts files
  [ -r "$user_kh" ] &&
      kh=( "${kh[@]}" "$user_kh" )
  [ -r ~/.ssh/known_hosts ] &&
      kh=( "${kh[@]}" ~/.ssh/known_hosts )
  [ -r ~/.ssh/known_hosts2 ] &&
      kh=( "${kh[@]}" ~/.ssh/known_hosts2 )
  [ -d ~/.ssh2/hostkeys ] &&
      khd=( "${khd[@]}" ~/.ssh2/hostkeys/*pub )

  # If we have known_hosts files to use
  if [ ${#kh[@]} -gt 0 -o ${#khd[@]} -gt 0 ]; then
      # Escape slashes and dots in paths for awk
      cur=${cur//\//\\\/}
      cur=${cur//\./\\\.}
      curd=$cur

      if [[ "$cur" == [0-9]*.* ]]; then
    # Digits followed by a dot - just search for that
    cur="^$cur.*"
      elif [[ "$cur" == [0-9]* ]]; then
    # Digits followed by no dot - search for digits followed
    # by a dot
    cur="^$cur.*\."
      elif [ -z "$cur" ]; then
    # A blank - search for a dot or an alpha character
    cur="[a-z.]"
      else
    cur="^$cur"
      fi

      if [ ${#kh[@]} -gt 0 ]; then

    # FS needs to look for a comma separated list
    COMPREPLY=( $( awk 'BEGIN {FS=","}
        /^[^|]/ {for (i=1; i/dev/null ) )
      fi
      if [ ${#khd[@]} -gt 0 ]; then
    # Needs to look for files called
    # .../.ssh2/key_22_.pub
    # dont fork any processes, because in a cluster environment,
    # there can be hundreds of hostkeys
    for i in "${khd[@]}" ; do
        if [[ "$i" == *key_22_$curd*.pub ]] && [ -r "$i" ] ; then
      host=${i/#*key_22_/}
      host=${host/%.pub/}
      COMPREPLY=( "${COMPREPLY[@]}" $host )
        fi
    done
      fi

      # append any available aliases from config files
      if [ ${#config[@]} -gt 0 ] && [ -n "$aliases" ]; then
    local host_aliases=$( sed -ne 's/^[Hh][Oo][Ss][Tt]\([Nn][Aa][Mm][Ee]\)\?['"$'\t '"']\+\([^*?]*\)$/\2/p' "${config[@]}" )
    hosts=$( compgen -W "$host_aliases" -- $ocur )
    COMPREPLY=( "${COMPREPLY[@]}" $hosts )
      fi

      # Now add results of normal hostname completion
      COMPREPLY=( "${COMPREPLY[@]}" $( compgen -A hostname -- $ocur ) )

      # apply suffix
      for (( i=0; i < ${#COMPREPLY[@]}; i++ )); do
    COMPREPLY[i]=$user${COMPREPLY[i]}$suffix
      done
  else
      # Just do normal hostname completion
      COMPREPLY=( $( compgen -A hostname -S "$suffix" -- $cur ) )
  fi

  return 0
}
Although, simply enough, with recent versions of bash most will just need (bashrc): # enable bash completion in interactive shells if [ -f /etc/bash_completion ]; then . /etc/bash_completion fi
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By: AJ
