Lecture 7 review
• What are environment variables?
– A set of dynamic values that can affect the execution of a process
– A process by default inherit the set of environment variables from
the parent process
• Most commands are executed from the shell program  they inherit
environment variables from the shell process.
• How can we see the environment variables in the shell process?
• How can we modify the value of environment variables in shell?
• Give two methods to access environment variables in a program.
Lecture 7 review
• What is a signal?
• How does a process typically react to a
signal?
• How many different ways a process can
react to a signal?
• How to install a signal handle?
• How to block a signal?