minishell

Description

This project is about creating a simple shell in C.

Commands

make
./minishell

Or,

make
./minishell [command]

to run a command directly through minishell

envp

$HOME is initialized as the $PWD (= the path) of the projet's root directory

Command prompt

The command prompt is composed of:

[$LOGNAME]@[$NAME / $SESSION_MANAGER]:[PATH]$

$NAME or $SESSION_MANAGER is used, depending on the system
Unsetting $LOGNAME or $NAME/$SESSION_MANAGER does not change the concerned part
When $HOME is unset, the current abosulte path is used.
If the current directory's path is equal to $HOME, the path is replaced by a tilde ('~')
If the current directory's position is lower than $HOME, the tilde does not appear
If the current directory is the root directory of all the system files, only "\$" is shown

Implemented commands

cd

The cd command updates $PWD and the path of the command prompt when the directory is changed
"cd .." works, as chdir() understands ".." as an argument
cd returns an error if it comes with more than a single argument
"cd" alone gets to $HOME

exit

Any argument is ignored

export

Every argument is exported to the minishell's envp, unless it is invalid.
An argument is invalid when:

The first character of the variable's name is a digit.
At least one of the characters in the variable's name is not alphanumeric, except for the underscore character ('_').
The argument begins with the assigning equal character ('=').
There is at least one space character before the equal character.

unset

Unsetting $PATH and requesting a command throws and error except when running the following implemented commands: cd, echo, exit, export, unset. This behavior is similar in bash.
Every argument is unset from the minishell's envp, unless the variable is not found, or is invalid.
An argument is invalid when:

The first character of the variable's name is a digit.
At least one of the characters in the variable's name is not alphanumeric, except for the underscore character ('_').

pwd

When $PWD is unset, the pwd command will print the current absolute path, using getcwd().

echo

Every argument will be printed, separated by a space, unless it begins with "-n", which will activate the -n option.
The character '\' is not echoed, as in bash.

env

Any argument is ignored
It prints all the environment variables that are active within minishell.

Leaks

To check all kinds of leaks while ignoring the onces dued to readline(), create a file with the following content:

{
	ignore_readline_leaks
	Memcheck:Leak
	...
	obj:/lib/x86_64-linux-gnu/libreadline.so.7.0
}

You can name this file anything you want.
On the last line, replace what follows "obj:" with the path corresponding to your own system.
The path appears inside the valgrind reports.

Then, run the following command:

valgrind --leak-check=full --show-leak-kinds=all --track-fds=yes  --suppressions=ignore_readline_leaks ./minishell

Here, the part following "--suppressions=" corresponds to the name of the file mentionned above.

daisvke / minishell