Toy UNIX shell with support for interactive/batch modes, aliasing & redirection. Once you enter a command, the shell forks a new child process, exec()'s the command while the parent wait()'s for its completion before continuing to the next iteration.

Running in interactive mode:

./mysh

Then wait for the shell to start before typing your commands.

mysh>

Running in batch mode:

./mysh batch_file

Your batch file should contain a list of commands, each on their own line, to be executed.

You can also redirect output to a file instead of stdout.

./mysh ls -la > output

(This runs the ls -la command and writes the output to the file output.)

To create an alias, run alias <command> <alias-name>. If alias-name was previously used, it is replaced.

mysh> alias ll /bin/ls -l -a

To see all aliases:

mysh> alias

To view a single alias:

mysh> alias <alias-name>

If alias-name exists, the shell will display its replacement value.

To unalias:

mysh> unalias <alias-name>

• Aliasing was implemented using a doubly-linked list to support arbitrary deletion.
• Most of the shell implementation is in mysh.c while aliasing functionality is defined in myalias.c.