RH033 RedHat Red Hat Linux Essentials Free Practice Exam Questions (2025 Updated)

This command will execute a program named My_program and whatever errors are generated while executing that program will all be added to a file named file2 rather than being displayed on the screen.

What is redirection of STDIN, STDOUT, STDERR in Linux?

Redirection means diverting data from their normal destination to another. Whenever a program is executed on terminal some output is displayed at the shell prompt. In case a user does not want that output to appear in the shell window, the user can redirect it elsewhere. The user can redirect the output into a file, printer, etc.

Not only the output of programs is redirected, but also input of a program and error messages are redirected to a file.

Common Redirection operators are as follows:

Answer option D is incorrect. This command will direct the standard output of My_program to file2.

Answer option A is incorrect. This command will append the standard output of My_program to file2.

Answer option C is incorrect. This command cannot be applied in this scenario.

In order to accomplish the task, you should create a recurring CRON job to delete the temporary files on the server.

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.

Using the -f option causes tail to continue to display the file in real time, showing added lines to the end of the file as they occur.

What is the tail -f command?

The tail command is used to display the last few lines of a text file or piped data. It has a special command line option –f (follow) that allows a file to be monitored. Instead of displaying the last few lines and exiting, tail displays the lines and then monitors the file. As new lines are added to the file by another process, tail updates the display.

This is particularly useful for monitoring log files. The following command will display the last 10 lines of messages and append new lines to the display as new lines are added to messages: tail -f /var/adm/messages

Answer option C is incorrect. The cat command simply shows the content of the file when it was last opened, cat does not continue to show updates of the file.

Answer option D is incorrect. The tail -n 3 /var/adm/messages command is used to show most recent entries in log file but it will not continue to show updates of the log file.

Answer option B is incorrect. The tail command will show the last few lines of the log file, but it will not continue to show updates of the log file.

You will use the yum install firefox command to install the package named firefox in the Linux system. This command will search the configured repositories for the package named firefox, and if found, will install the latest version, pulling in dependencies if needed.

Answer options B and D are incorrect. The -ivh and i options are not used with the yum command.

Answer option A is incorrect. The yum update firefox command is used to update a package in the Linux system. It is not used to install a package in Linux. If run without any specified package, the update option will update every currently installed package. If one or more packages are specified, yum will only update the listed packages. While updating packages, yum will ensure that all dependencies are satisfied.

The cat command concatenates both files foo.txt and student.txt together and | (pipe) will send the standard output of the cat command to the standard input of the less command, and this will show the output of both files on one screen at a time.

The shutdown -h now, halt -h, and poweroff -h commands can be used to shut down the Red Hat operating system immediately.

Answer option B is incorrect. This is an invalid answer and hence cannot be used to shut down the system.

The rm -rf commarecursively removes directories and its contents, ignoring warnings about removing write-protected files and directories.

Answer option B is incorrect. rm -f removes only files forcibly not a directory. To remove a directory and its contents forcibly, use -r in combination with -f with the rm command.

Answer option C is incorrect. The rmdir command is use to remove an empty directory.

Answer option D is incorrect. rm with no arguments deletes files.

The ls ~ and echo * commands can be used by a user to display the list of contents existing in his current user account. While ~ forces a command to perform queries in the user's home directory, ls displays the contents of the home directory.

The lpstat -t command lists all local and remote printers attached to your computer.

Answer options D and B are incorrect. The lpr and lpstat -d commands show the status of the default printer.

Answer option A is incorrect. The lpq command lists all jobs currently printing on the default printer.

The locate command queries a database for all pathnames that match the specified pattern. The specificity of locate can be increased by using it together with wildcards or other regular expressions. This command uses the star wildcard to display all files on the system that have the .xml filename extension.

What is a regular expression?

A regular expression is a way of describing a string of text using metacharacters or wildcard symbols.

For example, "*.xml" is a regular expression that refers to all files having the extension .xml.

What is a wildcard?

The specificity of LOCATE can be increased by using it together with wildcards or other regular expressions. Wildcards are characters that can be used to substitute for any other character or characters. For example, the star character (*) is a wildcard that can represent any single character or any string containing any number of characters.

Answer option A is incorrect. This is an incorrect syntax and an error messages will be displayed.

Answer option D is incorrect. The cat command displays the content of the specified file.

Answer option B is incorrect. This is an incorrect command, when you type this command an error message will be displayed.

Ctrl-w key-combination with an arrow key is used to jump from one window to another. This will move you to the next window in whichever direction the arrow would normally move your cursor. Instead of the arrow keys, you can also use

vi's traditional h, j, k and l keys for the same effect.

Answer options B and A are incorrect. Ctrl-w, s and Ctrl-w, v key-combinations are used to view a file in two windows in a single vim screen.

Ctrl-w, s splits the screen horizontally and Ctrl-w, v splits the screen vertically.

Answer option D is incorrect. Ctrl-w, q is used to quit from your current window.

You will use find ~ -perm -002 -exec chmod o-w {} \; command to fix other writable files in your home directory.

Answer option B is incorrect. The find /home -type d -ls command is used to do an ls -l style listing of all directories in /home/.

Answer options A and D are incorrect. There are no such commands in Linux.

A file can be viewed in two windows in a single vim screen by issuing Ctrl-w, s and Ctrl-w, v. The Keycombination

Ctrl-w, s splits the vim screen horizontally. The key-combination Ctrl-w, v splits the screen vertically.

Answer option C is incorrect. The Key-combination :wq is used to save a file and quit from the file in a vim text-editor.

Answer option D is incorrect. The key combination :q! is used to quit from a file without saving its contents.

What is vim?

Vim is an advanced text editor that seeks to provide the power of the Unix editor vi with a more complete feature set. Vim is useful whether a user is already using vi or using a different editor. Vim is a highly configurable text editor built to enable efficient text editing. It is an improved version of the vi editor distributed with most Unix systems. It is perfect for all kinds of text editing, from composing email to editing configuration files.

In order to know the name of the current shell, he will run the following command:

ECHO $shell

The command line interpreter in Linux is known as the shell. When a user runs a command, the shell interprets, processes, and executes the command and provides an output to the user. Linux comes with quite a few shells such as Bourne

Shell, Bourne Again Shell (BASH), C Shell, Korn Shell, etc. Bash is the most popular shell used by Linux users.

What is BASH?

The Bourne Again Shell (BASH) is a command language interpreter for the GNU's Not Unix (GNU) operating system. The following files are used to configure BASH:

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.

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.

When a user account is removed from a Linux system with the userdel command, the user account would get removed but some files and directories of that user may still remain on the system. To remove all items, the -r option is used with the userdel command.

The -f option forcibly removes the user account even if the user is still logged in. It also forces userdel to remove the user's home directory or his mail spool even if another user uses the same home directory or if the mail spool is not owned by the specified user.

Answer option C is incorrect. The -h option with the userdel command displays help messages and then exits.

Answer option D is incorrect. This command is incorrect. The -c option is not used with the userdel command.

Set user ID is the Linux access permission flag bit that allows users to run an executable file as the permissions of the executable's owner. When the Set user ID (SUID) bit is set and a user executes the file, the user will have the same rights as the owner.

If the Set user ID bit is set and the owner has the execute permission, the 'x' in the owner permissions is replaced by 's'. If the Set user ID bit is set and the owner has no execute permission, the 'x' is replaced by 'S'.

For example:

-rwsrw----The owner has the execute permission and the SUID bit is set.

-rwSr----- The SUID bit is set, but the owner has no execute permission.