Better version of the enhanced `cd` described in the `iselect(1)` man page

enhanced-cd.sh

#!bash

# database scan for enhanced cd command
cds() {
    (
        set -o pipefail
        # XXX: handle directories with newlines in their names?
        find "$HOME" -type d -print \
            | sort -u > "$HOME/.cdpaths"
        exit $?
    ) &
}

# definition of the enhanced cd command
cd() {
    if [ $# = 0 || -d "$1" ]; then
        builtin cd "$@"
    else
        builtin cd "$(
            # XXX: do we want to treat $1 as a regex?
            egrep "/$1[^/]*$" "$HOME/.cdpaths" \
                | iselect -a -Q "$1" -n "chdir" -t "Change directory to..."
        )"
    fi
    local ec=$?
    PS1='\u@\h:$PWD\n:> '
    return $ec
}

(Entirely untested.)