CSCI 352 - UNIX Software Development
Fall 2009 – Assignment 4
200 Points
Due: Wednesday, November 4 2009
For this assignment, we will continue work on the mini-shell. Start with
the code base you have for the last assignment. (ASSIGNMENT-3 tagged
sources.)
This assignment’s work consists of the following steps:
•Correct any problems you know about from Assignment 3. Specifically,
get the Makefile up to specifications.
•Add argument processing for arguments to msh’s main. This is not
argument processing for arguments produced by arg parse, it is for the
arguments passed to your shell when your shell starts. (The param-
eters to msh’s “int main (int mainargc, char **mainargv) ...”. The
name mainargc and mainargv could be any name, I just named them
that to show you that they are the argc and argv that are parameters
to main() for your shell.) This would be the arguments used when
your shell is run. For example, your msh could be run like:
msh filename arg1 arg2 arg3 arg4 arg5
instead of
msh
To add argument processing for main’s arguments, do the following:
–If the shell is started with one command line argument (the shell’s
name), all input comes from the standard input. This is consid-
ered an interactive execution. (This is what your msh currently
does. You start your msh by giving the command “msh”.)
–If the shell is started with more than one command line argument,
shell commands are read from the file named in the first argument
after the shell’s name. (The first argument is the script file name.
For example, you would start msh running with the command
“msh script arg1 arg2” and msh would read commands from the
file named “script”.) If msh can not open the file, msh should
print an error message and exit with the value of 127.
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