Simple Shell

A simple implementation of Shell.

Author

Ilan Kleiman

Compiling & Running

Compile:

$ make clean all

Run:

$ ./smash [-d] [filename]

Debugging

To see some basic debugging information, simply supply the -d flag upon execution of the smash binary.

$ ./smash -d

To see even more verbose debugging, compile the program via make with debug:

$ make clean debug

Then run the debug-binary the same way,

$ ./smash -d

Interactive & Non-Interactive Modes

There are two different modes, one mode is interactive - meaning upon execution it spawns a process that appears just like a shell would. The non-interactive mode is run by supplying the optional filename parameter to the smash executable.

Interactive

To run interactive mode, simply DO NOT supply a filename argument to the smash binary.

Non-Interactive

To run non-interactive mode, supply an executable file as a parameter to the smash binary.

$ ./smash SomeExecutableFile

Note: You may need to change permissions of the file before being able to run it.

$ chmod +x SomeExecutableFile

Executable file for non-interactive mode

To execute multiple commands, you must separate each command by a new line in the executable file.

echo hello
echo $PATH

Sample executable file.

Environment Variables

All the environment variables are accessible via the echo command and also other commands too. Prior to starting smash, you can set more environment variables using $ export SOMEKEY=SOMEVALUE.

The $PATH variable is parsed and upon execution of commands, smash looks in each of the path's given by the $PATH variable.