cpp_shell

A shell like program that allows different users chat and apply commands. A homework from NYCU network programming class.

Usage

cd 0812250/ and use command make
Open terminal and run np_single_proc <port_number> as server, ex: ./np_single_proc 8888
Open another terminal (or you can use tmux) and use telnet to connect, ex: telnet <ip_address> <port_number>
Enjoy each feature mentioned below

Features

Basic

Simple features can be implemented by yourself, there are a few built-in functions inside already (written by TAs of this class) Includes:

cat : same as cat from shell
ls : same as ls from shell
noop : a program that do nothing
number : Add number to each line of input
removetag : remove HTML tags and output to STDOUT
removetag0 : same as removetag but outputs error message to STDERR
any program you add to bin/

Built-in commands

setenv : set environment path
- setenv PATH <path>
printenv : print environment path
- printenv PATH

who : show information of all users

example:
% who
<ID> <nickname> <IP:port> <indicate me>
1 IamStudent 140.113.215.62:1201 <-me
2 (no name) 140.113.215.63:1013
3 student3 140.113.215.62:1201

tell : send message to another user
- % tell <user id> <message>
yell : send message to all users
- % yell <message>
name : change your name
- % name <new name>
exit : to exit the shell

Pipe

Redirect input or output by using '<' ans '>'
Allows normal pipe by using '|'

Allows number pipe by using "|" + number

ex: "|2" will pipe the STDOUT to the next next command

% removetag test.html | number
1
2 Test
3 This is a test program
4 for ras.
5

% removetag test.html |2
% ls
bin test.html test1.txt test2.txt

% number
1
2 Test
3 This is a test program
4 for ras.
5

Allows user pipe , allows user to pipe their STDOUT to another user, by using ">" + "userId"
- ex: you are user1, then you can user ">2" to pipe your STDOUT to user2, and user2 will need "<1"
- note that before the user you pipe to receive your piped message, you can't pipe other messages to him (but other users can)
- ```
user1:
% cat test.html >2

user2:
% cat <1
content from test.html
```
Note that you can not make one input pipe to two different places

You can get other user's pipe message and redirect it as normal message

ex: these commands are allowed

situation: you are user2 and user1 just piped some messages to you

% cat <1 | number
% cat <1 >3
% cat <1 |2
% cat <1 > test.txt

Examples

User1:

bash$ telnet nplinux1.nctu.edu.tw 7001
***************************************
** Welcome to the information server **
*************************************** # Welcome message
*** User ’(no name)’ entered from 140.113.215.62:1201. *** # Broadcast message of user login

% who
<ID> <nickname> <IP:port> <indicate me>
1 (no name) 140.113.215.62:1201 <- me

% name Jamie
*** User from 140.113.215.62:1201 is named ’Jamie’. ***

% ls
bin test.html

% *** User ’(no name)’ entered from 140.113.215.63:1013. *** # User 2 logins
who
<ID> <nickname> <IP:port> <indicate me>
1 Jamie 140.113.215.62:1201 <- me
2 (no name) 140.113.215.63:1013

% *** User from 140.113.215.63:1013 is named ’Roger’. *** # User 2 inputs ’name Roger’
who
<ID> <nickname> <IP:port> <indicate me>
1 Jamie 140.113.215.62:1201 <- me
2 Roger 140.113.215.63:1013

% *** User ’(no name)’ entered from 140.113.215.64:1302. *** # User 3 logins
who
<ID> <nickname> <IP:port> <indicate me>
1 Jamie 140.113.215.62:1201 <- me
2 Roger 140.113.215.63:1013
3 (no name) 140.113.215.64:1302

% yell Who knows how to make egg fried rice? help me plz!
*** Jamie yelled ***: Who knows how to make egg fried rice? help me plz!

% *** (no name) yelled ***: Sorry, I don’t know. :-( # User 3 yells
*** Roger yelled ***: HAIYAAAAAAA !!! # User 2 yells

% tell 2 Plz help me, my friends!

% *** Roger told you ***: Yeah! Let me show you the recipe # User 2 tells to User 1
*** Roger (#2) just piped ’cat EggFriedRice.txt >1’ to Jamie (#1) *** # Broadcast message of user pipe
*** Roger told you ***: You can use ’cat <2’ to show it!
cat <5 # mistyping
*** Error: user #5 does not exist yet. ***

% cat <2 # receive from the user pipe
*** Jamie (#1) just received from Roger (#2) by ’cat <2’ ***
Ask Uncle Gordon
Season with MSG !!

% tell 2 It’s works! Great!

% *** Roger (#2) just piped ’number EggFriedRice.txt >1’ to Jamie (#1) ***
*** Roger told you ***: You can receive by your program! Try ’number <2’!
number <2
*** Jamie (#1) just received from Roger (#2) by ’number <2’ ***
1 1 Ask Uncle Gorgon
2 2 Season with MSG !!

% tell 2 Cool! You’re genius! Thank you!
2

% *** Roger told you ***: You’re welcome!
*** User ’Roger’ left. ***
exit
bash$

User2

bash$ telnet nplinux1.nctu.edu.tw 7001 # The server port number
***************************************
** Welcome to the information server **
***************************************
*** User ’(no name)’ entered from 140.113.215.63:1013. ***

% name Roger
*** User from 140.113.215.63:1013 is named ’Roger’. ***

% *** User ’(no name)’ entered from 140.113.215.64:1302. ***
who
<ID> <nickname> <IP:port> <indicate me>
1 Jamie 140.113.215.62:1201
2 Roger 140.113.215.63:1013 <- me
3 (no name) 140.113.215.64:1302

% *** Jamie yelled ***: Who knows how to make egg fried rice? help me plz!
*** (no name) yelled ***: Sorry, I don’t know. :-(
yell HAIYAAAAAAA !!!
*** Roger yelled ***: HAIYAAAAAAA !!!

% *** Jamie told you ***: Plz help me, my friends!
tell 1 Yeah! Let me show you the recipe

% cat EggFriedRice.txt >1 # write to the user pipe
*** Roger (#2) just piped ’cat EggFriedRice.txt >1’ to Jamie (#1) ***

% tell 1 You can use ’cat <2’ to show it!

% *** Jamie (#1) just received from Roger (#2) by ’cat <2’ ***
*** Jamie told you ***: It’s works! Great!
number EggFriedRice.txt >1
*** Roger (#2) just piped ’number EggFriedRice.txt >1’ to Jamie (#1) ***

% tell 1 You can receive by your program! Try ’number <2’!

% *** Jamie (#1) just received from Roger (#2) by ’number <2’ ***
*** Jamie told you ***: Cool! You’re genius! Thank you!
tell 1 You’re welcome!

% exit
bash$