ln -s trick you can do with firejail, but with everything. In Python.

do to dot bin echo.sh

ln -s ~/.bin/lnstrick.py ~/.bin/echo

dot config lns-trick echo.args

MORE SUPER ECHO

lns-trick.py

#!/bin/python

import sys
import subprocess
import os
import sys
from pathlib import Path

def figure_path_list():
    got = os.getenv('LNS_TRICK_PATH')
    got = got and got.split(';') or []
    if len(got) == 0 or got[-1] == '+':
        return [os.getenv('HOME') + "/.config/lns-trick/", "/etc/lns-trick/",
                "/usr/share/lib/lns-trick/defaults/", ""] + got
    else:
        return got

def find_file(path_list, file):
    for p in path_list:
        uf = p + "/" + file + ".args"
        if Path(uf).is_file():
            return uf

def parse_file(fd, path_list):
    for line in fd.readlines():
        if line.startswith(':inc'):
            file = find_file(path_list, line[5:-1])
            if file:
                with open(file) as sfd:
                    yield parse_file(sfd, path_list)
#        elif line.startswith(':as line'):  # Better allow quotes?
#            yield line[9:-1]
#        elif line.startswith(':just print'):  # TODO maybe allow disabling..
#            assert line == ":just print\n"
#            yield 1
        else:
            assert not line.startswith(':'), "Dont have this command; " + line
            if line.startswith('\\'): line = line[1:]

            for el in line[:-1].split(" "):  # TODO quotation..
                yield el

def flatten(gen):
    for el in gen:
        if type(el) == str:
            yield el
        else:
            for sel in flatten(el):
                yield sel

def prog():
    path_list = figure_path_list()
    progname = sys.argv[0].split('/')[-1]
    file = find_file(path_list, progname)
    if file:
        with open(file) as fd:
            #print("\n".join(list(flatten(parse_file(fd, path_list)))
            #                + sys.argv[1:]))

            # TODO instead do $PATH, ignoring this program itself?
            subprocess.call(["/usr/bin/" + progname] +
                            list(flatten(parse_file(fd, path_list)))
                            + sys.argv[1:])
    else:
        print("Didn't find file for:", progname)

prog()