bash expand cd with shortcuts like zsh

Question

Is it possible in bash to expand something like

cd /u/lo/b<hit tab>

to

cd /usr/local/bin

?

Answer 1

Sorry I couldn't post earlier, I was held at work, and the bind function was more issue-prone than I first thought.

Here is what I came up with :

Bind the following script :

#!/bin/bash
#$HOME/.bashrc.d/autocomplete.sh
autocomplete_wrapper() {
    BASE="${READLINE_LINE% *} "           #we save the line except for the last argument
    [[ "$BASE" == "$READLINE_LINE " ]] && BASE="";  #if the line has only 1 argument, we set the BASE to blank
    EXPANSION=($(autocomplete "${READLINE_LINE##* }"))
    [[ ${#EXPANSION[@]} -gt 1 ]] && echo "${EXPANSION[@]:1}"  #if there is more than 1 match, we echo them
    READLINE_LINE="$BASE${EXPANSION[0]}"  #the current line is now the base + the 1st element
    READLINE_POINT=${#READLINE_LINE}      #we move our cursor at the end of the current line
}

autocomplete() {
    LAST_CMD="$1"
    #Special starting character expansion for '~', './' and '/'
    [[ "${LAST_CMD:0:1}" == "~" ]] && LAST_CMD="$HOME${LAST_CMD:1}"
    S=1; [[ "${LAST_CMD:0:1}" == "/" || "${LAST_CMD:0:2}" == "./" ]] && S=2; #we don't expand those

    #we do the path expansion of the last argument here by adding a * before each /
    EXPANSION=($(echo "$LAST_CMD*" | sed s:/:*/:"$S"g))

    if [[ ! -e "${EXPANSION[0]}" ]];then #if the path cannot be expanded, we don't change the output
        echo "$LAST_CMD"
    elif [[ "${#EXPANSION[@]}" -eq 1 ]];then #else if there is only one match, we output it
        echo "${EXPANSION[0]}"
    else
        #else we expand the path as much as possible and return all the possible results
        while [[ $l -le "${#EXPANSION[0]}" ]]; do
            for i in "${EXPANSION[@]}"; do
                if [[ "${EXPANSION[0]:$l:1}" != "${i:$l:1}" ]]; then
                    CTRL_LOOP=1
                    break
                fi
            done
            [[ $CTRL_LOOP -eq 1 ]] && break
            ((l++))
        done
        #we add the partial solution at the beggining of the array of solutions
        echo "${EXPANSION[0]:0:$l} ${EXPANSION[@]}"
    fi
}

with the following command :

    source "$HOME/.bashrc.d/autocomplete.sh" 
    bind -x '"\t" : autocomplete_wrapper'

Output :

>$ cd /u/lo/b<TAB>
>$ cd /usr/local/bin


>$ cd /u/l<TAB>
/usr/local /usr/lib
>$ cd /usr/l

The bind line could be added to your ~/.bashrc file, doing something like this :

if [[ -s "$HOME/.bashrc.d/autocomplete.sh" ]]; then
    source "$HOME/.bashrc.d/autocomplete.sh" 
    bind -x '"\t" : autocomplete_wrapper'
fi

(taken from this answer)

Furthermore, I would strongly advise against binding this command to your Tab key as it would override the default autocomplete.

Note: In some cases, this will misbehave, for isntance if you try to autocomplete "/path/with spaces/something", as the last argument to complete is determined by ${READLINE_LINE##* }. If this is an issue in your case, you should code a function that returns the last argument of a line when considering quotes

Feel free to ask for further clarification, and I welcome any suggestion to improve this script