Execute commands within loops. Execute commands conditionally. Send commands into the background. A process is an executing program. The kernel maintains a list of all processes.
Processes compete for CPU time.
Processes may spawn new child processes. The shell is a process. How the Shell Finds Commands Automatic path searching provides a convenient way to execute any accessible command. The particular sequence of directories searched is set by the PATH variable, and may be changed. It is easy to have a private version of a public command.