[Chapter 14] 14.7 Exercises
Author: Randal Schwartz, Tom Christiansen & Larry Wall
Date: 1999-07-02T01:35:12Z

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| Chapter 14 Process Management |

## 14.7 Exercises

See Appendix A, Exercise Answers for answers.

1. Write a program to parse the output of the date command to get the current day of the week. If the day of the week is a weekday, print `get` `to` `work`, otherwise print `go` `play`.

2. Write a program that gets all of the real names of the users from the /etc/passwd file, then transforms the output of the who command, replacing the login name (the first column) with the real name. (Hint: create a hash where the key is the login name and the value is the real name.) Try this both with the who command in backquotes and opened as a pipe. Which was easier?

3. Modify the previous program so that the output automatically goes to the printer. (If you can't access a printer, perhaps you can send yourself mail.)

4. Suppose the `mkdir` function were broken. Write a subroutine that doesn't use `mkdir`, but invokes `/bin/mkdir` with `system` instead. (Be sure that it works with directories that have a space in the name.)

5. Extend the routine from the previous exercise to employ `chmod` to set the permissions.

14.6 Sending and Receiving Signals |  | 15. Other Data Transformation