# Bash loadable modules



Or how to create new builtins for use in `bash`. Short answer: you can,
but it is not enabled by default (at least on my distribution, Ubuntu)

This is also something that is done much better in `zsh`.

Why do want this? *SPEED*! 

Shell scripting is a very easy
way to program, but forking all these helper programs takes
a lot of time. So one way to speed up your shell program is
to load these programs into the shell and making them a *builtin*.

# bash
I needed the bash source for this to work. So download it and
compile it. Then in the `examples/loadables` you have some
new builtins, like `cat`, `cut`, `head` and then some.

Making `cat` a builtin, you need the `enable` command

    $ type cat
    cat is /bin/cat

    $ enable -f /tmp/bash-3.2/examples/loadables/cat cat
    $ cat type
    cat is a shell builtin

Same goes for other executables. When updating my site with
`nanoblogger`, using `cat` and others as builtins made the
update much quicker. I shaved off some 20 seconds on a total
of 250 seconds; so it may be worth the effort.

 zsh
Here everything worked out of the box, but there is currently
no `cat` builtin for zsh (I created one). But there are
other interesting builtins.

What you need: `man zshmodules` and `zmodload`. With zmodload
you can create new builtins. 

For example, I made a `cat` builtin. Next I copy the `cat.so` to
`/usr/lib/zsh/4.3.4/zsh`

    % type cat
    cat is /bin/cat

    % zmodload zsh/cat
    % type cat
    cat is a shell builtin

Unload with `zmodload -u`. Works like a charm.