Functions for processes and process groups in perl

* alarm - schedule a SIGALRM
* exec - abandon this program to run another
* fork - create a new process just like this one
* getpgrp - get process group
* getppid - get parent process ID
* getpriority - get current nice value
* kill - send a signal to a process or process group
* pipe - open a pair of connected filehandles
* qx/STRING/ - backquote quote a string
* readpipe - execute a system command and collect standard output
* setpgrp - set the process group of a process
* setpriority - set a process's nice value
* sleep - block for some number of seconds
* system - run a separate program
* times - return elapsed time for self and child processes
* wait - wait for any child process to die
* waitpid - wait for a particular child process to die