This is a simple shell written in C, created for Operating Systems lab at Colgate University.
Built in commands:
To quit the shell, the user can type exit.
The shell runs in two different modes: sequential and parallel. In sequential mode, when multiple jobs are listed on a single command line, they are run one at a time to completion, in left-to right order. So, for the example above (/bin/ls ; /bin/ps), first /bin/ls should run to completion, then /bin/ps. In contrast, in parallel mode, all jobs are started in rapid succession. To switch between modes, type mode p or mode s. To display current mode, type mode.
There is PATH-like capability available: any paths for execution can be listed in shell-config. Note that these are only loaded upon running, and not dynamically updated upon every command.
The following 3 commands are specific to parallel mode:
jobs - prints out a list of all processes that are currently running in the background, including PID, command, and state
pause PID - sends a signal to the background child process with process ID [PID] in order to pause the process.
resume PID - sends a signal to a background child process that has been paused in order to restart it.