seanfxyz/nutsh

Elementary Unix shell, for educational purposes.

🥜 nutsh 🥜

An elementary Unix shell, for educational purposes.

https://github.com/SeanFxyz/nutsh

Written by Sean M Fitzgerald

[email protected]

Prerequisites

You must have a POSIX/Unix-like environment with a C compiler accessible via the cc command, and the POSIX standard libraries.

On Linux, *BSD, and similar systems you likely have these already. If not, look up how to install the basic development tools on your distribution.

On MacOS, you could install the official Apple Developer Tools package, but I would prefer to install Homebrew and then run brew install gcc make from the terminal to install the gcc and make packages.

If you'd like to try this out on Windows, I recommend Cygwin. Be sure to install Cygwin's gcc-core and make packages during setup.

Compiling

You can get the code by downloading a zip file from the GitHub page or by cloning the repository:

$ git clone [email protected]:SeanFxyz/nutsh.git

After acquiring the source code, enter the source code directory and simply run the make command:

$ cd nutsh
$ make

You can also run make debug to compile a version with debug symbols enabled for use with gdb or similar debugging tools.

Installing

You can install nutsh to your system by running make install with root privileges to copy the nutsh binary to /usr/bin/

If you don't have root privileges, you can also copy the binary to ~/.local/bin/, which is likely to be in your path, and can easily be added if it isn't already.

Features

Commands

At present, nutsh will run any program in your $PATH as well as four builtin commands:

• help: displays builtin commands
• cd: changes the current directory
• pwd: prints the current directory
• exit: terminates the shell

Pipes

Pipes from one program to another are supported, but are not compatible with builtin commands.

To pipe from one program to another, type a command that outputs to stdout, like ls, then a pipe | character with with spaces on either side, then another command that reads from stdin, like grep, all on the same line, like this:

🥜$ ls Movies/ | grep -i nut
Nutcracker.mp4
The Nut Job.mp4
The Nutty Professor.mp4
🥜$

You should be able to chain as many commands as you like this way:

🥜$ ls Movies/ | grep -i nut | cowsay -n
 _________________________
/ Nutcracker.mp4          \
| The Nut Job.mp4         |
\ The Nutty Professor.mp4 /
 -------------------------
        \   ^__^
         \  (oo)\_______
            (__)\       )\/\
                ||----w |
                ||     ||
🥜$

nutsh's Issues

Add some comments to darr.c and darr.h to explain how they work.

Although it isn't used that frequently, the dynamic array (darr) implementation could use some clarification.