Simple shell

our main objective is to make a simple shell while implementing the basic built in commands

Write a UNIX command line interpreter.

Usage: simple_shell Your Shell should:

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. The 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)

Simple shell 0.1 +

Handle command lines with arguments

Simple shell 0.2 +

Handle the PATH fork must not be called if the command doesn’t exist

Simple shell 0.3 +

Implement the exit built-in, that exits the shell Usage: exit You don’t have to handle any argument to the built-in exit

Simple shell 0.4 +

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

Simple shell 0.1 +

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 You don’t have to:

be able to move the cursor

Simple shell 0.2 +

You are not allowed to use strtok imple shell 0.4 +

handle arguments for the built-in exit Usage: exit status, where status is an integer used to exit the shell

Simple shell 1.0 +

Implement the setenv and unsetenv builtin commands

setenv Initialize a new environment variable, or modify an existing one Command syntax: setenv VARIABLE VALUE Should print something on stderr on failure unsetenv Remove an environment variable Command syntax: unsetenv VARIABLE Should print something on stderr on failure

Simple shell 1.0 +

Implement the builtin command cd:

Changes the current directory of the process. Command syntax: cd [DIRECTORY] If no argument is given to cd the command must be interpreted like cd $HOME You have to handle the command cd - You have to update the environment variable PWD when you change directory man chdir, man getcwd

Simple shell 1.0 +

Handle the commands separator ;

Simple shell 1.0 +

Handle the && and || shell logical operators

Simple shell 1.0 +

Implement the alias builtin command Usage: alias [name[='value'] ...] alias: Prints a list of all aliases, one per line, in the form name='value' alias name [name2 ...]: Prints the aliases name, name2, etc 1 per line, in the form name='value' alias name='value' [...]: Defines an alias for each name whose value is given. If name is already an alias, replaces its value with value

Simple shell 1.0 +

Handle variables replacement Handle the $? variable Handle the $$ variable

simple shell 1.0 +

Handle comments (#)

Simple shell 1.0 +

Usage: simple_shell [filename] Your shell can take a file as a command line argument The file contains all the commands that your shell should run before exiting The file should contain one command per line In this mode, the shell should not print a prompt and should not read from stdin Repo:

GitHub repository: simple_shell