This is the Simple Shell project, a command line interpreter developed in C as part of the ALX Software Engineering program. The Simple Shell mimics basic functionalities of a Unix shell, providing users with an interactive interface to execute commands.

At the end of this project, you are expected to be able to explain to anyone, without the help of Google:

• Who designed and implemented the original Unix operating system
• Who wrote the first version of the UNIX shell
• Who invented the B programming language (the direct predecessor to the C programming language)
• Who is Ken Thompson
• How does a shell work
• What is a pid and a ppid
• How to manipulate the environment of the current process
• What is the difference between a function and a system call
• How to create processes
• What are the three prototypes of main
• How does the shell use the PATH to find the programs
• How to execute another program with the execve system call
• How to suspend the execution of a process until one of its children terminates
• What is EOF / “end-of-file”?

• Implement a command line interpreter
• Handle command lines with arguments
• Handle the PATH to locate executable programs
• Implement built-in commands like exit and env
• Write your own getline function
• Handle logical operators && and ||
• Implement cd, setenv, and unsetenv built-ins
• Implement command separators ;
• Implement file input mode for the shell
• Implement the alias built-in command
• Handle variables replacement (e.g., $? and $$)
• Handle comments in the shell (using #)
• Accept a file as input for batch processing

To compile the Simple Shell, use the following command:

gcc -Wall -Werror -Wextra -pedantic -std=gnu89 *.c -o hsh