Mitris Victor
334 CC
Homework 2 MINI-SHELL

Implementation unui mini-shell

I used the parser received.

For the implementation of the extern commands I declared ext_comanda functions which has the following paramters:
	*a vector of char*
	*a struct simple_comand_t
This function creates a child, redirects to stdin, stdout and stderr based on in, out and err fields in struct and executes the command returning Exit_Failure if it failes.

The function parse_simple receives as parameters:
	* a simple_command_t struct
	* level ( the level in the heap )
	* the parent of the command
this function verifies what kind of command is executed : internal (cd, exit, quit ), setting an environment variable, extern commands
Functia parse_simple primeste ca parametri o structura simple_command_t, level care reprezinta nivelul in arbore si parintele comenzii.
Aceasta verifica ce fel de comanda se doreste a se executa:
	-comenzi interne (cd, exit, quit) - se apeleaza shell_cd respectiv shell_exit
	-setarea unei variabile de sistem - se executa functia var_sys
	-comenzi externe se executa functia ext_comanda


The function do in parallel receives as parameters 2 commands cmd1 and cmd2, the level in heap and the parent of the commands.
THis function creates a child process that executes command1, the parent executes command2 and then waits for the response of the child.