A simple wrapper for ssh-keygen command to manage known_hosts file

completion.bash

_ssh_known_hosts()
{
    local cur prev
    _get_comp_words_by_ref cur prev

    COMPREPLY=($(compgen -W 'find forget list' -- "${cur}"))
}
complete -F _ssh_known_hosts ssh-known-hosts

ssh-known-hosts

#!/bin/sh

usage()
{
    echo "$(basename "$0") [-f known_hosts_file] {find|forget|list} {hostname|[hostname]:port}"
}

known_hosts_file="${HOME}/.ssh/known_hosts"

while getopts f:h option; do
    case "${option}" in
    f)
        known_hosts_file="${OPTARG}"
        ;;
    h)
        usage
        exit
        ;;
    esac
done
shift $((OPTIND - 1))

if [ $# -eq 0 ]; then
    echo 'no command specified' 1>&2
    exit 1
fi

case "$1" in
find)
    if [ -z "$2" ]; then
        echo 'no hostname specified' 1>&2
        exit 1
    fi
    ssh-keygen -f "${known_hosts_file}" -F "$2"
    ;;
forget)
    if [ -z "$2" ]; then
        echo 'no hostname specified' 1>&2
        exit 1
    fi
    ssh-keygen -f "${known_hosts_file}" -R "$2"
    ;;
list)
    cat "${known_hosts_file}"
    ;;
*)
    echo "unknown command: $1" 1>&2
    exit 1
    ;;
esac