This is ctypes.sh, a foreign function interface for bash.

ctypes.sh is a bash plugin that provides a foreign function interface directly
in your shell. In other words, it allows you to call routines in shared
libraries from within bash.

A (very) simple example will help illustrate:

$ dlcall puts "hello, world"
hello, world

# A more complex example, use libm to calculate sin(PI/2)
$ dlopen libm.so.6
0x172ebf0
$ dlcall -r double sin double:1.57079632679489661923
double:1.000000

ctypes.sh can extend bash scripts to accomplish tasks that were previously
impossible, or would require external helpers to be written.

ctypes.sh makes it possible to use
GTK+ natively in
your shell scripts, or write a high-performance http daemon.

See more examples here

prerequisites

ctypes.sh is dependent on the following libraries and programs:

• libffi
• bash
• libelf (optional)
• elfutils (optional)
• libdwarf / libdw (optional)

Fedora

For recent Fedora, this should be enough:

sudo yum install elfutils-devel dnf-utils

Now you can use the debuginfo-install command to install debugging symbols for automatic structure support.

Ubuntu

For recent Ubuntu, this should be enough:

sudo apt install autoconf libltdl-dev libffi-dev libelf-dev elfutils libdw-dev

If you want to use automatic struct support (recommended), you should also make
you have ddebs available.

install

ctypes.sh can be installed from source like this:

$ git clone https://github.com/taviso/ctypes.sh.git
$ cd ctypes.sh
$ ./autogen.sh
$ ./configure
$ make
$ [sudo] make install

By default ctypes.sh is installed into /usr/local/bin and
/usr/local/lib. You can overload the prefix path by defining the
PREFIX environment variable before installing.

$ PREFIX=$HOME make install

example

source ctypes.sh
puts () {
  dlcall puts "$@"
  return $?
}

puts "hello, world"

Here is what people have been saying about ctypes.sh:

• “that’s disgusting”
• “this has got to stop”
• “you’ve gone