Workshop

The Workshop summarizes the key terms you learned and poses some questions about the topics presented in this chapter. It also provides you with a preview of what you will learn in the next hour.

Key Terms

command block A list of one or more shell commands that are grouped in a conditional or looping statement.

conditional expression This is an expression that returns either true or false.

determinate loop A loop where the number of times the loop is run is known before the loop is started.

expression This is a command that returns a value.

indeterminate loop A loop where the number of times the loop is run is not known before the loop is started.

loop This is a sequence of commands that are repeatedly executed while a condition is true.

variables These are names to label data that may change during the execution of a program.

zero-length variable A variable that does not have a value assigned to it.

Exercises

1:How would you read in an address in a shell program? How would you read in a name?
2:If you read in the number of people who read a newspaper, and the number of people who subscribe to a particular paper, how would you determine the ratio of subscribers to readers?
3:How do you know whether a file has data?
4:How do you wait for data to be placed in a file?

Preview of the Next Hour

In the next hour, you are introduced to managing processes in UNIX. You learn how to start a background job, how to switch between foreground and background, and how to terminate a command.

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