simple_shell

This repository contains all you need to know about the simple shell project. This is a school project with the aim of building a command interpreter (shell) withand the objective of knowing how shell works behind the hooks.

Non built-in

This software can execute non built-in commands directly with the kernel. You may beasking yourself how did you implemented communication with the kernel. When a command is enter it checks all the execution files in the /bin directory if the specified command execution file exist then get it's required full path e.g /bin/ls or Type: which command (e.g ls) It can also execute commands without their full path e.g ls

Inbuilt Commands

In-built commands are commands we implement that doesn't exist in the the /bin directory. Some of these commands are as follows:

exit:

• This is use to exit the shell. It exit with a default status except specified. Usage: exit Usage with argument: exit <status>

env:

• This command list all the environment variable Usage: env

setenv:

• This command set an environment variable if it does not exist reset it if it exist. Usage: setenv <VARIABLE_NAME> <value>

unsetenv:

• This command unset an environment variable Usage: unsetenv <VARIABLE_NAME>

cd:

• This command changes the specified directory or the home directory if no directory was specified. It c hanges to the previous directory if "-" is passed as a n argument Usage: cd <DIR_NAME>

command separaror

• The shell can execute multiple commands from a single input seperated by a semicolon. Usage: /bin/ls ; env

logical operators on commands

• The shell uses normal logical operators to control the flow of command execution in a single input. The AND operator stop executing futher commands if a command returns an error. While the OR operator executes futher even after encountering an error. Usage: ls && pwd and pwd || /bin/ls

Passing commands through a file

• The shell can take a file that contains commands seperated by newline and executes the commands when executed in non-interactive mood. Usage: ./hsh <FILE_NAME>

This project is still ongoing and there might be some failures some times.