RH033 Questions and Answers

According to the question, the permission set requires setting SID with the owner and the group.

Moreover, the Read, Write, and Execute permissions on the script file are required for the owner, Read and Execute permissions for the group, and Read permission for others.

The chmod command is used to change the permissions. The last three digits, i.e., 754 will provide the required permissions to the owner, group, and others. The digit 7 will provide the Read, Write, and Execute permissions to the owner.

The digit 5 will provide the Read and

Execute permissions to the group. The digit 4 will provide the Read permission to others.

According to the question, you have to set SID for the owner and users. For the owner (SUID), you will have to add 4 as a prefix to the permission number. For the group (SGID), you will have to add 2 as a prefix to it. For setting both the

SIDs (SUID and SGID), you will have to add 6 as a prefix to the permission set. Hence, in order to accomplish the task, you will have to run the following command:

chmod 6754

This will set the SID for the owner and group on the permission set of the lf.cgi script file. When SID is set, the Execute permission symbol x is replaced with s.

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 fdisk command is a menu-based command available with Linux for hard disk configuration. This command can perform the following tasks:

Delete a partition on a hard disk.

Create a partition on a hard disk.

Change the partition type.

Display the partition table.

Note: The sfdisk command-line utility is an alternative to the fdisk command.

Answer option C is incorrect. In Linux, the mount command is used to mount and display disks, partitions, and file systems. Mounting refers to the process in which the operating system prepares the media to be read.

Anwer option D is incorrect. The File System Check (fsck) command is used to scan all disks and partitions, and it repairs them if required. The

fsck command should be run only on an unmounted file system.

Note: The function of the fsck command is similar to that of the Window's scandisk utility.

Answer option B is incorrect. There is no such command as crpar in Linux.

The ipconfig network diagnostic tool is used in the Windows operating system to see IP addresses and MAC addresses, and other related information. It is not used in the Linux operating system. In the place of the ipconfig utility, ifconfig is used in Linux for performing the same task.

Answer option D is incorrect. The ping utility is a network diagnostic tool that checks TCP/IP connectivity on any host. It is used in both Linux and Windows operating systems.

What is the ping utility?

The ping command-line utility is used to test connectivity with a host on a TCP/IP-based network.

This is achieved by sending out a series of packets to a specified destination host. On receiving the packets, the destination host responds with a series of replies. These replies can be used to determine whether or not the network is working properly.

Answer option A is incorrect. This is a network diagnostic tool in Linux that perform hostname to IP address translation and vice versa.

Answer option B is incorrect. This is a network diagnostic tool in Linux which is used to perform hostname to IP address translations, and vice versa in greater detail.

This is the correct syntax for granting ownership of foofile to John.

What is the chown command?

The chown command is used to change the ownership of a file. Only root can change the ownership of a file. The chown command can be used with the -R option to recursively change the ownership of an entire directory tree.

Syntax:

chown [-R] newowner filename

Answer option B is incorrect. The chmod command is used to change access mode for files and directories.

Answer option D is incorrect. The syntax of this command is not correct. With chown, first write the name of the user whom you want to give ownership, then write the filename of the file whose ownership you want to change.

Answer option C is incorrect. The chgrp command is used to change Group-ownership not file ownership.

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

According to the question's requirement, the following time specifications can be set for the cron

job:

30 17 * * 5

30 17 * * FRI

In this time specification, you can define five parameters. The first two parameters define minutes and hours of the day. The last or the fifth parameter shows the day of the week. It can be the name or the number of a day. Numbers 0 and 7 are for Sunday, whereas from Monday to

Saturday, the numbers are from 1 to 6.

smbclient is a command-line tool that provides access to SMB/CIFS shares.

What is the smbclient command?

smbclient is a command-line tool that provides access to SMB/CIFS shares. smbclient is a samba client with an "ftp like" interface. It is a useful tool to test connectivity to a Windows share. It can be used to transfer files, or to look at share names. In addition, it has the ability to backup and restore files from a server to a client and visa versa.

Example:

#smbclient -L server1

The above command will list all shares on server1.

Some useful options are as follows:

Answer option C is incorrect. scp copies files between hosts on the Linux network.

Answer option A is incorrect. rsync is a fast and extraordinarily versatile file copying tool. It can copy locally, to/from another host over any remote shell or to/from a remote rsync daemon.

What is rsync?

In computing, rsync is a software application for Unix systems. It synchronizes files and directories from one location to another while minimizing data transfer using delta encoding. It can copy or display directory contents and copy files, optionally using compression and recursion.

In daemon mode, rsync listens to the default TCP port of 873, serving files in the native rsync protocol or via a remote shell such as RSH or SSH. In the latter case, the rsync client executable must be installed on both the local and remote hosts.

Answer option B is incorrect. mutt is a small but very powerful text based program for reading electronic mail under Linux operating systems.

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.

According to the scenario, you will use newgrp command to accomplish the task. The newgrp command is used to temporarily change the primary group of a user into another group of which that user is a member. In this step, a new shell will be created, and when that user will exit from the shell, his previous group will be reinstated. If no group is specified, the GID is changed to the login GID.

Answer option C is incorrect. John will not use the chgrp command to accomplish his task. The chgrp (from change group) command is used by unprivileged users to change the group associated with a file. Unlike the chown command, chgrp allows regular users to change groups, but only to one of which they are a member. The general syntax of the chgrp command is as follows:

chgrp group target1 [target2 ..]

The group parameter indicates the new group with which the targets should be associated.

The target1 parameter indicates the files or directories for which the change should be made.

The target2 parameter indicates the optional additional files or directories for which the change should be made.

For example:

The above command changes the group associated with ttt to 'system', provided the executing user is a member of that group.

Answer option D is incorrect. John will not use the chown command to accomplish his task. The chown command is used to change the user and/or group ownership of each given file as specified by the first non-option argument as follows: if only a user name (or numeric user ID) is given, that user is made the owner of each given file, and the file's group is not changed.

If the user name is followed by a colon and a group name (or numeric group ID), with no spaces between them, the group ownership of the files is changed as well.

The syntax of the chown command is as follows: chown [-R [ -H | -L | -P ]] [ -h ] owner[:group] file ...

Answer option A is incorrect.

The chmod command is used to change the access mode of a file. The syntax of the command is: chmod who=permissions filename

Here, "who" refers to the owner of the file, group members, or other users, and permissions refers to "rwx".

For example, chmod 755 File.txt will give all access permissions to the owner and the read and execute permissions to the group members and other users.

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

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:

Answer option B is incorrect. The nice command is used to change the priority of a process in the kernel's scheduler. A niceness of -20 is the highest priority and 19 is the lowest priority. The default niceness for processes is inherited from its parent process, usually 0. For example, when specifying a very low priority, the following command can be entered: nice -n 19 cc -c *.c &

The above command runs the cc command in the background at a lower priority than the default priority set by the nice command.

Answer options D and A are incorrect. There are no such spell checkers as inspell and spell.

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 appends that 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.

You can view all running processes with the help of the ps -aux command. Hence, any of the ps –aux commands (i.e., ps -aux | grep cc, ps -aux

| more, or ps -aux) can be used to check whether the cc process is running on the computer.

Answer option B is incorrect. 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

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

The VI is a visual interactive text editor that allows a user to create, modify, and store files on a Linux computer. It works in the following modes:

Command: This is the default mode of the command. Various commands can be used in this mode to manipulate the opened text.

Input: In this mode, a user can insert text directly in the text screen area.

Answer option D is incorrect. The GNU zip (GZIP) utility is a compression utility that is used to compress files for saving space. It creates files with the .gz extension. It can also compress tar files. In order to unzip files with the .gz extension, the

GUNZIP command is used.

Answer option B is incorrect. The nmap utility, also commonly known as port scanner, is used to view the open ports on a Linux computer. It is used by administrators to determine which services are available for external users. This utility helps administrators in deciding whether to disable the services that are not being used in order to minimize any security risk.

Answer option C is incorrect. MS Word is a Windows-based utility. Hence, it cannot be used in Linux.