RH033 Sample Questions Answers

The second column in the listing shows the number of hard links created for the file.

You will use the ssh command to remotely login to the host York and then remotely execute the command 'df -h' to check the disk space usage on the remote system.

The Evolution and Mozilla are the Graphical Mail clients in Red Hat Enterprise Linux.

According to the scenario, John wants to change the modified date and time of the file private.txt to a desired date and time. For this, he can use either the touch -t or touch -d command. The difference between these two commands is that the touch -d command is more flexible, while the touch -t command takes the date and time in the format MMDDhhmm.ss.

The nl install.log and sed = install.log commands can be used to assign a line number to every line of the install.log file.

Answer options C and D are incorrect. The wc -c install.log and wc -m install.log commands will print the number of bytes and the number of characters, respectively.

The $! environmental variable represents the PID value of the last child process.

Answer option D is incorrect. The $$ environmental variable represents the PID of the running shell.

Answer option A is incorrect. The $? environmental variable results in the value zero if the last command was executed successfully, otherwise it displays the value one.

Answer option C is incorrect. It is an invalid Linux standard environmental variable.

The ifdown command is used to set down the interface and flush all its addresses. It is possible to let

ifdown check the interface if the interface is still used before setting it down. If the interface is used it may then discard the using processes or refuse setting it down.

To enable this feature, check /etc/sysconfig/network/config file.

Answer option A is incorrect. The ifup command is used to bring up a preconfigured interface for networking. It is usually invoked by the network script at boot time or by the PCMCIA/hotplug system. It can also be used to start interfaces manually on the command line. It activates the link, adds addresses and other parameters and sets up the routes for an interface.

Answer option C is incorrect. The ifconfig commands displays the basic settings of a network device.

Answer option D is incorrect. There is no such command as down.

The date command with the %M specifier prints the current time (Minutes). Since the output is redirected towards the date.txt file, the current time (Minutes) will be printed in the date.txt file.

The evince utility is used to view the PDF files in Linux.

Answer option A is incorrect. The ps2pdf utility creates the PDF files.

Answer option C is incorrect. The pdf2ps utility converts the PDF files to PostScript.

Answer option B is incorrect. The a2ps utility converts text to PostScript and sends it to the print queue or file.

The zip -r foobar.zip filesdir command is used to create a file named foobar.zip and put it into the directory named filesdir. foobar.zip represents the file you are creating and filesdir represents the directory you want to put in the new zip file. The -r option specifies that you want to include all files contained in the filesdir directory recursively.

Answer option A is incorrect. The unzip foobar.zip command is used to extract the contents of a zip file to the filesdir directory.

Answer option D is incorrect. The gunzip foobar.zip command is used to expand the compressed file.

Answer option C is incorrect. The tar -tvf foobar.tar command is used to list the contents of a tar file.

The ls command is used to list files on a Linux computer. The syntax of the ls command is as follows:

ls [option] [directory name]

Several options are used with the ls command. Following is a list of some important options:

For example, the following command displays all the files (including hidden files) in the /home directory and the contents in the subdirectories:

What is >> command?

The >> command is used for storing the output generated by different commands. It creates a file specified to store the output. If the specified file already exists, it appends that file.

Answer option A is incorrect. The > command is used for storing the output generated by different commands. It creates a file specified to store the output. If the specified file already exists, it overwrites that file.

Answer options C and B are incorrect. Improper syntax has been followed in these answer options.

The evince utility is used to view PDF files on the Linux operating system.

What is the evince command?

The evince command is a document viewer capable of displaying multiple and single page document formats such as PDF and Postscript.

Syntax:

evince [Options] [Filename]

Answer options B and D are incorrect. These commands are used to convert a text to PostScript and send it to a file or the print queue.

What is PostScript?

PostScript is a language developed by Adobe Systems for printing documents on laser printers. It can also be adapted to produce images on other types of devices. It is the standard for desktop publishing. Every PostScript printer contains a built-in interpreter that executes PostScript instructions. Level 1, Level 2, and PostScript 3 are three basic versions of PostScript language.

Answer option A is incorrect. The ps2pdf utility is used to create PDF files.

The cat data.txt.* command will display both the splitted files, and the > command will redirect the output into a new data.txt file.

What is the cat command?

The concatenate (cat) command is used to display or print the contents of a file.

Syntax: cat filename

For example, the following command will display the contents of the /var/log/dmesg file: cat /var/log/dmesg

Note: The more command is used in conjunction with the cat command to prevent scrolling of the screen while displaying the contents of a file.

What is > command?

The > command is used for storing the output generated by different commands. It creates a file specified to store the output. If the specified file already exists, it overwrites that file.

Answer option A is incorrect. This command will open a new file data.txt.* into the vi editor.

Answer option D is incorrect. This command will give the vi editor a warning "output is not to a terminal" since the vi terminal cannot be redirected into the data.txt file.

Answer option B is incorrect. The less command displays only the first file data.txt.aa, and the > command redirects the output into the data.txt file. Hence, John will not get the desired output using this command.

aspell is a utility that can function as an ispell -a replacement, as an independent spell checker, as a test utility to test out Aspell features, and as a utility for managing dictionaries.

Syntax:

aspell [options]

Some important options used with aspell are as follows:

The following options may be used with the aspell command to control which dictionaries to use and how they behave:

Answer option A is incorrect. The tee command is used to split the output of a program so that it can be seen on the display and also be saved in a file. It can also be used to capture intermediate output before the data is altered by another command or program. The tee command reads standard input, then writes its content to standard output, and simultaneously copies it into the specified file(s) or variables.

The syntax of the tee command is as follows: tee [-a] [-i] [File] where, the -a option appends the output to the end of File instead of writing over it and the -i option is used to ignore interrupts.

Answer option B is incorrect. The concatenate (cat) command is used to display or print the contents of a file.

Syntax:

cat filename

For example, the following command will display the contents of the /var/log/dmesg file:

cat /var/log/dmesg

Note: The more command is used in conjunction with the cat command to prevent scrolling of the screen while displaying the contents of a file.

Answer option D is incorrect. There is no such utility as dict in Linux.

If no path is given, find looks in the current directory and its subdirectories. Using the -i option tells the find command to perform caseinsensitive search for files named snow.html. It will show all files named snow.html, Snow.html,

SNOW.html in the current directory.

Answer option B is incorrect. This command will only search for files named snow.html in the current directory with case-sensitiveness. It will not search for those files named Snow.html, SNOW.html.

Answer option C is incorrect. This is an incorrect command; it will show an error message.

Answer option D is incorrect. This is also an incorrect command, there should be a name after -i in the command.

If the package is not yet installed, the yum deplist httpd command is used to get the list of packages that httpd depends on.Answer option C is incorrect. The yum list httpd command can be used to list various information about available packages. For example, it lists all available and installed packages and all packages with updates available in the yum repositories.

Answer option D is incorrect. If the package is already installed, the rpm -qR httpd command is used to get the list of packages that this package depends on.

Answer option A is incorrect. This command is incorrect. The deplist option is not used with the rpm command.

In order to run the script, you are required to add the execute permission to the script file. The permission can be assigned through the chmod command.

What is the chmod command?

The chmod command is used to change file access permissions in Linux.

Syntax:

chmod [option] [mode]

Option: The following is a list of some important options that can be provided with the command:

Mode: Mode is written in the following format:

[ugoa] [+-=] [rwxXstugo]

The combination of ugoa specifies the users for whom the file access permissions will be changed. In ugoa, u is for the user who owns the file, g is for other users in the file group, o is for other users not in the file group, and a is for all users.

The operator + adds the specified permissions to the existing permissions of each file. The - operator removes, and the = character specifies that the specified permissions are the only permissions for that file.

The combination of rwxXstugo is permission type. In rwxXstugo, r is for read, w is for write, x is for execute, X is to execute only if the file is a directory or already has execute permission for some user, s is to set user or group

ID on execution, t is to save program text on swap device, u are the permissions that the user who owns the file currently has for it, g are the permissions that other users in the file group have for the file, and o are the permissions that other users not in the file group have for the file.

pgrep looks through the currently running processes and lists the process IDs that match the selection criteria to stdout. All the criteria have to match. pkill is a tool that looks up or signals processes based on name and other attributes. Pkill will send the specified signal (by default SIGTERM) to each process instead of listing them on stdout.

Answer option A is incorrect. The top command is used to produce a frequently-updated list of processes. By default, the processes are ordered by percentage of CPU usage, with only the "top" CPU consumers shown. This command shows how much processing power and memory are being used, as well as other information about the running processes. The following figure demonstrates the output of the top command:

Answer option C is incorrect. The sort command is used to print the lines of its input or concatenation of all files listed in its argument list in sorted order. Sorting is done based on one or more sort keys extracted from each line of input. By default, the entire input is taken as the sort key. The blank space is taken used as the default field separator in the output of the sort command.

The -r flag, however, reverses the sort order. For example, the ls -s | sort -nr command will sort the directories of the root directory in reverse order of size.

The ps command reports the status of processes that are currently running on a Linux computer.

What is > command?

The > command is used for storing the output generated by different commands. It creates a file specified to store the output. If the specified file already exists, it overwrites that file.