Change directory with CDPATH support.

_cd.sh

# Change directory with CDPATH support. Culled from the bash-completion package.

_compopt_o_filenames () 
{ 
    type compopt &> /dev/null && compopt -o filenames 2> /dev/null || compgen -f /non-existing-dir/ > /dev/null
}

_filedir () 
{ 
    local i IFS='
' xspec;
    _tilde "$cur" || return 0;
    local -a toks;
    local quoted tmp;
    _quote_readline_by_ref "$cur" quoted;
    toks=(${toks[@]-} $(
        compgen -d -- "$cur" | {
            while read -r tmp; do
                # TODO: I have removed a "[ -n $tmp ] &&" before 'printf ..',
                #       and everything works again. If this bug suddenly
                #       appears again (i.e. "cd /b<TAB>" becomes "cd /"),
                #       remember to check for other similar conditionals (here
                #       and _filedir_xspec()). --David
                printf '%s\n' $tmp
            done
        }
    ));
    if [[ "$1" != -d ]]; then
        [[ ${BASH_VERSINFO[0]} -ge 4 ]] && xspec=${1:+"!*.@($1|${1^^})"} || xspec=${1:+"!*.@($1|$(printf %s $1 | tr '[:lower:]' '[:upper:]'))"};
        toks=(${toks[@]-} $( compgen -f -X "$xspec" -- $quoted));
    fi;
    [ ${#toks[@]} -ne 0 ] && _compopt_o_filenames;
    COMPREPLY=("${COMPREPLY[@]}" "${toks[@]}")
}

_cd () 
{ 
    local cur IFS='
' i j k;
    _get_comp_words_by_ref cur;
    if [[ "$cur" == ?(\\)\$* ]]; then
        COMPREPLY=($( compgen -v -P '$' -- "${cur#?(\\)$}" ));
        return 0;
    fi;
    _compopt_o_filenames;
    if [[ -z "${CDPATH:-}" || "$cur" == ?(.)?(.)/* ]]; then
        _filedir -d;
        return 0;
    fi;
    local -r mark_dirs=$(_rl_enabled mark-directories && echo y);
    local -r mark_symdirs=$(_rl_enabled mark-symlinked-directories && echo y);
    for i in ${CDPATH//:/'
'};
    do
        k="${#COMPREPLY[@]}";
        for j in $( compgen -d $i/$cur );
        do
            if [[ ( -n $mark_symdirs && -h $j || -n $mark_dirs && ! -h $j ) && ! -d ${j#$i/} ]]; then
                j="${j}/";
            fi;
            COMPREPLY[k++]=${j#$i/};
        done;
    done;
    _filedir -d;
    if [[ ${#COMPREPLY[@]} -eq 1 ]]; then
        i=${COMPREPLY[0]};
        if [[ "$i" == "$cur" && $i != "*/" ]]; then
            COMPREPLY[0]="${i}/";
        fi;
    fi;
    return 0
}

_quote_readline_by_ref () 
{ 
    if [[ ${1:0:1} == "'" ]]; then
        if [[ ${BASH_VERSINFO[0]} -ge 4 ]]; then
            printf -v $2 %s "${1:1}";
        else
            printf -v $2 %q "${1:1}";
            printf -v $2 %q ${!2};
        fi;
    else
        if [[ ${BASH_VERSINFO[0]} -le 3 && ${1:0:1} == '"' ]]; then
            printf -v $2 %q "${1:1}";
        else
            printf -v $2 %q "$1";
        fi;
    fi;
    [[ ${!2:0:1} == '$' ]] && eval $2=${!2}
}

_rl_enabled () 
{ 
    [[ "$( bind -v )" = *$1+([[:space:]])on* ]]
}

_tilde () 
{ 
    local result=0;
    if [[ ${1:0:1} == "~" && $1 == ${1//\/} ]]; then
        _compopt_o_filenames;
        COMPREPLY=($( compgen -P '~' -u "${1#\~}" ));
        result=${#COMPREPLY[@]};
    fi;
    return $result
}

complete -o nospace -F _cd cd