All Unix shell commands can be wrraped by symbol $. Its command arguments, command options, standard output handler and standard error handler can be manipulate by special methods that the name starts with $.

In other words, methods that the name starts with $ acts as a DSL.

Here is an example that we use the shorthand helper of hyexec, which bounds some useful Unix command wrapper to global namespace.

hyexec = require 'hyexec'
hyexec.global()
git.add.$args('.').commit.push.$run()

require \hyexec .global!
git.add.$args \. .commit.push.$run!

creates a dynamic wrapper to an existed Unix command.

{$} = require \hyexec

$args is used to add a argument,

ls = $ 'ls'
ls.$args '/tmp'
ls.$command!             # ls /tmp

or remove a argument.

ls
  .$args '/tmp', false   # remove /tmp from arguments.
  .$command!             # ls

$opts is used to add a option.

ls.$opts a:on,l:on
ls.$command! # ls -al

or remove a option.

ls.$opts 'a', 'l', false # remove -a -l from options.
ls.$command!             # ls

$flags is a shorthand of $opts for boolean type command option.

ls.$flags 'f'
ls.$command! # ls -a -l -f

besides, $args,$opts, $flags can be used together.

rsync = $ 'rsync'
rsync
  .$opts rsh:\ssh
  .$flags 'a', 'z'
  .$args '/tmp'
  .$args 'server:dest'
  .$command!             # rsync -a -z --rsh='ssh' /tmp server:dest

$ supports Command Group also, such as git, bzr.

git = $ 'git'
git
  .add
  .$args '.'
  .commit
  .$opts m, 'hello'
  .push
  .$command! # git add .; git commit -m hello; git push

make Cmd.methods that the name starts with $ is callable object to set command arguements and command options one times as the above example.

ls = $ 'ls'
ls '-al'
ls a:on

git = $ 'git'
git
  .add \.
  .commit m:\hello
  .push!
  .$command!