0x16. C - Simple Shell

Write a UNIX command line interpreter.

TASK 1

1. Simple shell 0.1

• Display a prompt and wait for the user to type a command. A command line always ends with a new line.
• The prompt is displayed again each time a command has been executed.
• he command lines are simple, no semicolons, no pipes, no redirections or any other advanced features.
• The command lines are made only of one word. No arguments will be passed to programs.
• If an executable cannot be found, print an error message and display the prompt again.
• Handle errors.
• You have to handle the “end of file” condition (Ctrl+D)

execve will be the core part of your Shell, don’t forget to pass the environ to it…

TASK 2

2. Simple shell 0.2

• Handle command lines with arguments

TASK 3

3. Simple shell 0.3

• Handle the PATH

TASK 4

4. Simple shell 0.4

• Implement the exit built-in, that exits the shell
• Usage: exit

TASK 5

5. Simple shell 1.0

• Implement the env built-in, that prints the current environment

TASK 6

6. Simple shell 0.1.1

• Write your own getline function
• Use a buffer to read many chars at once and call the least possible the read system call
• You will need to use static variables
• You are not allowed to use getline

TASK 7

7. Simple shell 0.2.1

• You are not allowed to use strtok