AShar97 / mysh

A simple shell in c. Period.

mysh

This is a readme file for MYSH : A simple shell created in c by Ayush, Yugansh & Ojasvin. Period.

1. General Description
2. Compiling
3. Flow of control
4. Other details

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1) General Description

Three main steps for a shell is:-

1. Get the command from standard input.
2. Parse it into arguments and function.
3. Execute required job.

2) Compiling

Execute shell code by typing :-

$ make mysh

Clean the output by typing :-

$ make clean

3) Flow of Control

Execute shell code by typing :-

$ ./mysh

Program begins with executing "mysh_userinterface();" in main(), which is a continuos loop, breaks on status FALSE. In this "mysh_read_line(); " reads a line from the keyboard, mysh_split_line() splits it into command + arguments amd "mysh_execute();" execute the command and looping continues until exit is encountered.

In mysh_execute() it runs two types of command one is builin and other is default terminal command. For eg, cd is a builtin command which cannot be executed by a child process forking system because it will only change the directory of the child process which executes it. Parent process directory is not changed.

4) Other details

timerun command -- > this command is used to kill a running process after a particular time.

Syntax :- timerun <process_name>

eg :- timerun 2 ./a.out

this command will execute ./a.out for two seconds and then kill it.