Describe the PAGER environment variable.

In response to your query on a library function, man returns a page on an identically named user command. Why does this happen?

Where are the HOWTO documents located on a typical Linux system?

Name the program that displays GNU Texinfo pages.

What is probably the most important skill you can offer to end users while staffing a helpdesk service?

Run a man inquiry as follows:

$ man -a -Pless mkfifo

There is both a mkfifo command and a mkfifo function. You'll be looking at the mkfifo command from section 1 of the manual. Note MKFIFO(1) at the top of the page.

Press the letter q to terminate the pager program. The pager is then invoked again and displays the mkfifo function from section 3 of the manual. Note MKFIFO(3) at the top of the page.

Run the man command again, using the -Pmore option as follows:

$ man -a -Pmore mkfifo

Run another man inquiry as follows:

$ man -d ln

Now examine the man configuration file:

$ less /etc/man.config

Notice how the contents of this file coincide with the result you received from the -d option.

Enter the following command:

$ locate whois

Note that locate shows two commands that match whois, along with a directory and a README file.

Now use the stat program to evaluate the two commands:

$ stat /usr/bin/whois /usr/bin/fwhois

Examine the inode number for both files. An inode is a unique identifier, or node, of your Linux filesystem. The fact that these two files show the same inode indicates that they are links to the same file. That is, one file has two directory entries with different names. This means that you'll be running the same program regardless of which command name you use.

Next, examine the README file that locate reported:

$ less /usr/doc/fwhois-1.00/README

Your version may be different. Now look for a manpage and an info page for this program:

$ man fwhois
$ info fwhois

As you can see, the program author chose not to offer a manpage or an info page for fwhois, leaving the README in /usr/doc as the sole documentation for the program.

Suppose you are Spanish-speaking and would like to learn about how to use Linux in your native tongue. Try the following commands:

$ man spanish
$ info spanish
$ find /usr/doc -name "*anish*"

Using a Usenet news reader program, subscribe to comp.os.linux and comp.os.linux.advocacy.

Using a text editor, create a text file named mycmd.1. Complete the following steps:

Use the man facility to investigate the halt command. Based on what you find there, answer the following:

Evaluate the other commands:

From what you see in the manpages:

After successfully following your instructions, the user calls again. This time he is puzzled by error messages that are produced when his users attempt a clean shutdown from multiuser mode using the shutdown command without arguments.