Free Practice Questions for RedHat RH033 Exam

According to the scenario, John can use the set +o history command to disable history.

Answer option D is incorrect. John cannot use the set -o history command to accomplish his task.

This command is used to enable disabled history.

Answer option A is incorrect. John cannot use the history !! command to accomplish his task. This command is used to see the most recently typed command.

Answer option C is incorrect. John cannot use the history !N command to accomplish his task. This command is used to display the Nth history command.

What is the history command?

In the bash shell, the history command is used to view the recently executed commands. History is on by default. A user can turn off history using the command set +o history and turn it on using set -o history. An environment variable

HISTSIZE is used to inform bash about how many history lines should be kept. The following commands are frequently used to view and manipulate history:

You will use the tee command to write its content to standard output and simultaneously copy it into the specified file. 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 C 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 A is incorrect. The less command is used to view (but not change) the contents of a text file, one screen at a time. It is similar to the more command. However, it has the extended capability of allowing both forward and backward navigation through the file. Unlike most Unix text editors/viewers, less does not need to read the entire file before starting; therefore, it has faster load times with large files.

The command syntax of the less command is as follows: less [options] file_name

Where,

Answer option D is incorrect. The more command is used to view (but not modify) the contents of a text file on the terminal screen at a time.

The syntax of the more command is as follows: more [options] file_name

Where,

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.

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.

The mput command is used to upload multiple files simultaneously.

Answer option C is incorrect. The put command uploads one file each time you use the command. It is not used to upload multiple files at a time.

Answer option D is incorrect. The get command is used to download one file at a time.

Answer option B is incorrect. The mget command is used to download multiple files at a time. It is not used to upload multiple files.

The traceroute -w command is used to make traceroute wait 5 seconds (default) for a response to a packet.

What is traceroute?

Traceroute is a route-tracing utility that displays the path an IP packet takes to reach its destination.

It uses Internet

Control Message Protocol (ICMP) echo packets to display the Fully Qualified Domain Name (FQDN) and the IP address of each gateway along the route to the remote host. Traceroute sends out a packet to the destination computer with the TTL field value of 1. When the first router in the path receives the packet, it decrements the TTL value by

1. If the TTL value is zero, it discards the packet and sends a message back to the originating host to inform it that the packet has been discarded. Traceroute records the IP address and DNS name of that router, and sends another packet with a TTL value of

2. This packet goes through the first router, and then times out at the next router in the path. The second router also sends an error message back to the originating host. Now, the process starts once again and

traceroute continues to send data packets with incremented TTL values until a packet finally reaches the target host, or until it decides that the host is unreachable. In the whole process, traceroute also records the time taken for a round trip for each packet at each router.

Answer option B is incorrect. The traceroute -T command uses the TCP/SYN packets for probing.

Answer option C is incorrect. The traceroute -q command sets the number of probe packets per hop.

The default value is 3.

Answer option D is incorrect. The traceroute -r command bypasses the normal routing tables and sends the probe packet directly to a host on an attached network. If the host is not on a directly-attached network, an error is returned. This option can be used to ping a local host through an interface that has no route through it.

The read permission has been assigned to the owner of the file and the read permission has also been assigned to members of its owing group.

The first field - represents the type of a file and the next three characters (rwx) represent the permission given to the owner of the file then the next three characters (r--) represent the permission given to the group to which the file belongs and the last three characters (---) represent the permission given to others.

Answer option C is incorrect. No permission has been assigned to others users.

The /etc/X11/xdm/xdm-config file is the default configuration file of XDM. The X Window Display

Manager (XDM) is the default display manager for the X Window System. XDM is distributed as part of XFree86 and is configured by a series of files located in /etc/X11/XDM. Some of the important files of XDM are given below in the list:

Xaccess: It is used to control inbound requests from remote hosts.

Xresources: This file holds configuration information for XDM resources and the graphical login screen. It can be edited to modify the appearance of the XDM login screen. Xservers: This file is used to associate the X display names with either the local X server software or a foreign display such as an X terminal.

Xsession: This file contains the script XDM launches after a successful login.

Xsetup_0: This file defines how XDM will open. It is a script started before the graphical login screen.

It often includes commands to set colors, display graphics, or run other programs. This script is executed as root.

XDM-config: This file is used to configure XDM configuration resources.

Answer option B is incorrect. $HOME/.Xauthority is the user authorization file where XDM stores keys for clients to read.

Answer option D is incorrect. The /usr/bin/xterm file is the default session program of XDM.

Answer option C is incorrect. It is not a valid XDM configuration file.

This command looks for files on the system whose data has been changed exactly five days ago.

The scp command is used to copy files from one host to another over the network.

What is the scp command?

The scp command is used to copy files over ssh connections. This is pretty useful if a user wants to transport files between computers, for example, to backup a file. The scp command uses the ssh command to copy files over the network.

Syntax:

# scp [options] source destination

Where, source refers to the file which a user wants to copy from his current computer/directory, and destination refers to the home directory of the remote system where a user wants to copy the file.

Some important options used with the scp command are as follows:

Answer option A is incorrect. The ls command in Linux lists information about files (the current directory by default).

Answer option C is incorrect. The mutt command is used to manage email within a text only environment.

Answer option B is incorrect. The cat command is used to join multiple files together and display the result on the screen.