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

password entry For each account on the UNIX system, there is an entry in the account database known as the password file. This also contains an encrypted copy of the account password. This set of information for an individual account is known as the password entry.

recursive command A command that repeatedly invokes itself.

shell alias Most UNIX shells have a convenient way for you to create abbreviations for commonly used commands or series of commands, known as shell aliases. For example, if I always found myself typing ls -CF, an alias can let me type just ls and have the shell automatically add the -CF flags each time.

Exercises

1:What's the differences between cp and mv?
2:If you were installing a program from a floppy disk onto a hard disk, would you use cp or mv?
3:If you know DOS, this question is for you. Although DOS has a RENAME command, it doesn't have both COPY and MOVE. Which of these two do you think DOS includes? Why?
4:Try using mkdir to create a directory. What happens and why?
5:You've noticed that both rmdir and rm -r can be used to remove directories. Which is safer to use?
6:The rm command has another flag that wasn't discussed in this hour. The -f flag forces removal of files regardless of permission (assuming you're the owner, that is). In combination with the -r flag, this can be amazingly destructive. Why?

Preview of the Next Hour

The seventh hour introduces the useful file command, which indicates the contents of any file in the UNIX file system. With file, you will explore various directories in the UNIX file system to see what the command reveals about different system and personal files. Then, when you've found some files worth reading, you will learn about cat, more, and pg, which are different ways of looking at the contents of a file.

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