btrfs-ls

#!/bin/bash
safe_source () { [[ ! -z ${1:-} ]] && source $1; _dir="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"; _sdir=$(dirname "$(readlink -f "$0")"); }; safe_source

# show help
show_help(){
    cat <<HELP

    $(basename $0) [options] path/to/dir[/]

    Notice: The "/" character at the end works like in rsync. 

    Options:
        --ro, --only-ro           : List only readonly snapshots
        --rw, --only-rw           : List only read-write snapshots
        --relative                : Print relative path

HELP
    exit
}

die(){
    echo 
    echo "ERROR: $@"
    echo
    exit 1
}

# Parse command line arguments
# ---------------------------
# Initialize parameters
only_ro=false
only_rw=false
relative=false
# ---------------------------
args_backup=("$@")
args=()
_count=1
while :; do
    key="${1:-}"
    case $key in
        -h|-\?|--help|'')
            show_help    # Display a usage synopsis.
            exit
            ;;
        # --------------------------------------------------------
        --only-ro|--ro)
            only_ro=true
            ;;
        --only-rw|--rw)
            only_rw=true
            ;;
        --relative)
            relative=true
            ;;
        # --------------------------------------------------------
        -*) # Handle unrecognized options
            die "Unknown option: $1"
            ;;
        *)  # Generate the new positional arguments: $arg1, $arg2, ... and ${args[@]}
            if [[ ! -z ${1:-} ]]; then
                declare arg$((_count++))="$1"
                args+=("$1")
            fi
            ;;
    esac
    shift
    [[ -z ${1:-} ]] && break
done; set -- "${args_backup[@]}"
# Use $arg1 in place of $1, $arg2 in place of $2 and so on, 
# "$@" is in the original state,
# use ${args[@]} for new positional arguments  

errcho () { >&2 echo -e "$@"; }

[[ $(whoami) = "root" ]] || { sudo $0 "$@"; exit 0; }

filter=''
[[ $only_ro = true ]] && filter='if($3 == "readonly")'
[[ $only_rw = true ]] && filter='if($3 == "-")'

while read i; do
    [[ -z $i ]] && continue
    if [[ $arg1 =~ ^.*/$ ]] && [[ $i/ =~ ^$arg1$ ]]; then
        errcho "INFO: Skipping $i"
        continue
    else
        if $relative; then
            [[ "$arg1" != "$i" ]] && realpath --relative-to="$arg1" "$i"
        else
            echo "$i"
        fi
    fi
done <<< $($_sdir/btrbk ls "$arg1" \
    | sed -n '1!p' \
    |  awk '{'"$filter"' print}' \
    | awk '{$1=""; $2=""; $3=""; print}' \
    | sort -r)