SHCL is

1. a very customizable shell made with secret alien technology, and
2. an unholy union of POSIX Shell and Common Lisp.

Behold Common Lisp embedded in POSIX shell embedded in Common Lisp! Notice that the Common Lisp form embedded in the shell expression can access the lexical environment.

(let ((rld "rld"))
  (capture (:stdout)
    #$ echo Hello ,(concatenate 'string "Wo" rld) | wc -c #$))
; => "12"

Now lay your eyes on a lisp function participating in a pipeline!

shcl> : ,(shcl/core/debug:graph-dependencies) | dot -Tpng > graph.png

SHCL is only really tested against SBCL, but it should be portable to other lisp compilers. Be aware that ECL is known to be problematic because it tries to reap child processes automatically.

First, you’ll need to install some dependencies. To start with, you’ll need Clang and libedit. There’s also some Common Lisp dependencies that need to be taken care of: SBCL, Quicklisp, and cffi-grovel. If you’re new to building Common Lisp projects, you might want to let Roswell set up your lisp environment for you.

# Set up Clang, libedit, and Roswell
make LISP='ros -s cffi-grovel run --'

You can skip Roswell if you want. Just make sure that you set LISP to a command that runs SBCL with Quicklisp and cffi-grovel loaded. For example,

# Set up Clang, libedit, SBCL, and Quicklisp
QUICKLISP_SETUP=~/quicklisp/setup.lisp # or wherever you installed quicklisp
make LISP="sbcl --no-userinit --load \"$QUICKLISP_SETUP\" --eval '(ql:quickload :cffi-grovel)'"

I don’t know what you’re expecting to see here. Its a POSIX-like shell. You can do (almost) all your normal POSIX shell stuff in it.

shcl> echo foobar
foobar
shcl> FOO=$(echo echo foo; false) || echo assignment returned false
assignment returned false
shcl> $FOO
foo
shcl> { echo foobar ; echo baz ; echo blip ; } | tail -n 1
blip
shcl> shcl-enable-lisp-syntax
shcl> if [ ,(+ 1 2 3) = ,(* 2 3) ]; then
> echo woah
> fi
woah
shcl> shcl-repl
shcl (lisp)> (format t "Hello world~%")
Hello world
NIL
shcl (lisp)> (define-builtin set-env (&option print &required var value)
> (loop :for str :across print :do (format t "~A~%" str))
> (setf (env var) value)
> 0)
SET-ENV
shcl (lisp)> ^D
shcl> set-env --print hi --print there VAR value | wc -l
2
shcl> echo $VAR
value
shcl> ^D

Okay, actually, that kind of went off the rails.