Project 2: File Redirection in the Shell

Due Tuesday, November 28

For this project, add support for shell variables to our demo shell. For this, create a shell builtin command called "export", with similar functionality to BASH's export command. If the user includes a variable name, with $, replace the variable name with the value of the variable. Use the environment to store variables, getenv to get values, and setenv to set them. If a variable doesn't exist, treat it as an empty string, and replace the variable's name with spaces for parsing. At minimum, your export must support the following:

Running "export" alone should print out a list of environment variables and their values.
Running "export VARNAME=VALUE" should work.
Running a command with a variable name should work, like "echo $HOME"