Chapter 10  -  Processes and Signals.system1.c   -  A program that calls another program using the system command.system2.c   -  system1.c revised so that the other program is run in the background.pexec.c    -  A program that replaces a process image using the execlp command.fork1.c     -  A program that duplicates a process image using the fork command.wait.c     -  A program that uses the wait command to wait for a child process to finish.fork2.c    -  fork1.c changed so thata zombie process is created.upper.c    -  A simple program to convert all characters to upper case.file.txt   -  A short text file for use with upper.c.useupper.c -  A program that demonstrates that open file descriptors are preserved across a call to execl.ctrlc1.c    -  A simple signal handling program which reacts to SIGINT.alarm.c    -  A program which sends a signal to itself.ctrlc2.c   -  A signal handling progam that uses sigaction rather than signal.