fish-shell/share/functions/__fish_complete_tar.fish

function __fish_complete_tar -d "Peek inside of archives and list all files"

    set -l cmd (commandline -poc)
    set -e cmd[1]
    for i in $cmd
        switch $i
            case '-*'
                continue

            case '*.tar.bz' '*.tar.bz2' '*.tbz' '*.tbz2'
                if test -f $i
                    set -l file_list (tar -jt <$i)
                    printf (_ "%s\tArchived file\n") $file_list
                end
                return

            case '*.tar.gz' '*.tgz'
                if test -f $i
                    set -l file_list (tar -it <$i)
                    printf (_ "%s\tArchived file\n") $file_list
                end
                return

            case '*.tar.xz'
                if test -f $i
                    set -l file_list (tar -Jt <$i)
                    printf (_ "%s\tArchived file\n") $file_list
                end
                return

            case '*.tar'
                if test -f $i
                    set -l file_list (tar -t <$i)
                    printf (_ "%s\tArchived file\n") $file_list
                end
                return
        end
    end
end