shell_functions

#!/bin/sh
rmknownhost() {
    local KNOWN_HOSTS_FILE="${HOME}/.ssh/known_hosts"
    local USAGE="Usage: rmknownhost [-f] line#\n\n"
    OPTIND=1

    while getopts f opt; do
        case $opt in
            f) local FORCE=1;;
            ?)
                printf "${USAGE}"
                return 2
                ;;
        esac
    done

    shift $((OPTIND-1))

    local LINE=$@

    if [ -z "${LINE}" ]; then
        printf "${USAGE}"
        return 2
    fi

    if [ ! -r "${KNOWN_HOSTS_FILE}" ]; then
        printf "Known hosts file %s is not readable!\n" "${KNOWN_HOSTS_FILE}"
        return 2
    fi

    if [ ! -w "${KNOWN_HOSTS_FILE}" ]; then
        printf "Known hosts file %s is not writeable!\n" "${KNOWN_HOSTS_FILE}"
        return 2
    fi

    test ${LINE} -eq 1 >/dev/null 2>&1
    
    if [ $? -gt 1 ]; then
        printf "Invalid line number '%s'\n" ${LINE}
        return 2
    fi

    local COUNT=$(sed -n $= "${KNOWN_HOSTS_FILE}")

    if [ ${COUNT} -lt ${LINE} ]; then
        printf "Line number %d out of range\n" ${LINE}
        return 2
    fi

    local HOST=$(awk 'NR=='${LINE}' {print $1;exit}' "${KNOWN_HOSTS_FILE}")

    if [ ${FORCE:-0} -ne 1 ]; then
        local INPUT=

        printf "Delete '%s' [y/N]? " "${HOST}"
        read INPUT

        while true; do
            case "${INPUT}" in
                y|Y) break;;
                n|N|'') return 0;;
                *) printf "Delete '%s' [y/N]? " "${HOST}"; read INPUT;;
            esac
        done
    fi
   
    local SCRIPT="${LINE}d"
    local TEMP_FILE="${KNOWN_HOSTS_FILE}.${RANDOM}${RANDOM}"

    if [ -f "${TEMP_FILE}" ]; then
        printf "Temp file %s exists, aborting\n" "${TEMP_FILE}"
        return 2
    fi

    sed "${SCRIPT}" "${KNOWN_HOSTS_FILE}" > "${TEMP_FILE}" 2>/dev/null

    if [ $? -ne 0 ]; then
        printf "Error creating temp file %s, aborting\n" "${TEMP_FILE}"
        rm -f "${TEMP_FILE}" >/dev/null 2>&1
        return 2
    fi

    mv -f "${TEMP_FILE}" "${KNOWN_HOSTS_FILE}" >/dev/null 2>&1

    if [ $? -ne 0 ]; then
        printf "Error replacing file %s\n" "${KNOWN_HOSTS_FILE}"
    fi

    rm -f "${TEMP_FILE}" >/dev/null 2>&1
}

settitle() {
    printf "\033]0;%s@%s:%s\007" "${USER}" "${HOSTNAME%%.*}" "${PWD/#$HOME/~}"
}