CS620 Spring 2008 Assignment 7

CS 620

Assignment 7

Due Date: 5/2/2008 (Friday)

Maximum grade: 50 points

Note: The program is due by midnight on the due date.

Late Policy:
1 day late -- 5% deducted
2 days late -- 10% deducted
3 days late -- 15% deducted
4 days late -- 20% deducted
5 days late -- 25% deducted
> 5 days late -- don't bother!

The objective of this assignment is to get you familiar with process management system calls. You will write a small shell that will support the following features:

regular commands

I/O redirection (only standard in and standard out -- not standard error)

Your shell should be able to handle commands like:

%ls -l

% cat file > junk

% cat < junk > junk1

Your shell should treat the following as non-recognized commands:

%ls -l | more
% Command not found: ls -l | more

(That is, your shell need not handle pipes.)

% cat file > junk junk3
% Command not found: cat file > junk junk3

% ddddddddddd
% Command not found: ddddddddddd

Your shell is also not expected to execute the cd command.

% cd
% Command not found: cd

I expect that any code you write will include meaningful comments. Don't write tricky code. A 1 line function is typically a lot harder to understand than the same function written using 20 lines. Besides, the executables for both the 1 line function and the 20 line function are usually of the same size.

SUBMIT INSTRUCTIONS: Your assignment is due by midnight, Friday, May 2nd. Create a make file to build your executable file. The name of your executable must be myshell. Submit all your source files (no object or executable files) and makefile by typing

      ~cs620/submit 7 file1 file2 file3 ...

where 7 is the number of this assignment. Note that if you want to resubmit, then you need to use 7a, 7b, ... for assignment number (not 7).

Test Commands for Assignment 7

Your shell should be able to handle commands: here.

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