RH033 Sample Questions Answers

The most likely cause of the issue is that David does not have the Write permission on the Sales directory.

The listing of the directory shows that root is the owner of the Sales directory. The permissions on the Sales directory are rwxr-xr-x. The permission character set has three sets of three permissions that are Read, Write, and Execute. The first set, which is rwx, represents the

Read, Write, and Execute permissions to the owner of the file. The second set, which is r-x, provides the Read and Execute permissions to the group root. The third set, which is r-x, provides the Read and Execute permissions to other users.

In order to resolve the issue, you will have to make David the owner of the Sales directory. For this, you will have to run the following command:

chown david sales

After becoming the owner of the directory, David will automatically get the Write permission, and he will be able to store his files in the directory.

Setting permissions on files and folders in Linux

Answer option B is incorrect. As the listing shows that David is not the owner of the folder, this will not make any difference.

Answer options D and C are incorrect. According to the question, the directory is properly listed, and mounting or deletion is not an issue.

Since John wants to use the variable VAR1 as an environmental variable, he will use the export command to accomplish the task.

The useradd or adduser command is used to add a user on the Linux operating system.

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.

According to the scenario, John will execute the foo && bar; command. Because of the && operator, bar will execute if and only if foo completes successfully.

Answer option C is incorrect. The foo; bar; command sequence will run foo and bar in a sequential manner, but the successful completion of the first command does not matter.

Answer option D is incorrect. The foo || bar; command sequence will run the bar if and only if foo fails to complete successfully.

Answer option B is incorrect. In the foo | bar; command sequence, the output of the foo command will be the input for the bar command.

The scp command copies files between hosts on a network. It uses ssh for data transfer, and uses the same authentication and provides the same security as ssh. Unlike rcp, scp will ask for passwords or passphrases if they are needed for authentication. Any file name may contain a host and user specification to indicate that the file is to be copied to/from that host.

Copies between two remote hosts are permitted.

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.

Pidgin (formerly named Gaim) is a multi-platform instant messaging client, based on a library named

libpurple. Libpurple has support for many commonly used instant messaging protocols, allowing a user to log into various different services from one application.

What is Pidgin?

Pidgin is a multi-protocol Instant Messaging client that allows a user to use all of his IM accounts at once. It is a free software that can work with AIM ,Gadu-Gadu, Jabber, ICQ ,IRC, MSN, SILC, XMPP, Yahoo!, and Zephyr Network. Anyone is free to use it and modify it, but if a user distributes his modifications, he must distribute the modified source code as well.

The license of this communication software is Freeware, i.e. anyone can freely download and use this communication software.

Answer options A and D are incorrect. Evolution and Thunderbird are Graphical mail clients in Linux.

It is not an Instant Messenger.

What is Evolution?

Evolution is a full-featured personal and workgroup information management tool for Linux systems, and is the default email client for Red Hat Enterprise Linux. It provides all of the standard email client features, including powerful mailbox management, user-defined filters, and quick searches. Its additional feature is a flexible calendar/scheduler, which allows users to create and confirm group meetings and special events online.

What is Thunderbird?

Mozilla Thunderbird is a free, open source, cross-platform e-mail and news client developed by the

Mozilla Foundation.

Thunderbird can manage multiple e-mail, newsgroup and RSS accounts and supports multiple identities within accounts.

Thunderbird incorporates a Bayesian spam filter, a white list based on the included address book, and can also understand classifications by server-based filters such as SpamAssassin. Thunderbird provides enterprise and government-grade security features such as SSL/TLS connections to IMAP and SMTP servers. It also offers native

support for S/MIME secure email (digital signing and message encryption using certificates).

Answer option B is incorrect. mutt is an email client that manages emails within a text-only environment. It is not an Instant Messenger.

What is mutt? mutt is a powerful tool for managing email within a text-only environment. This tool is very important to access email even when a graphical interface is not available. Some of its strengths are handling of message threads and flexibility. When mutt sees a series of related messages, it displays each reply under the parent. mutt supports sending of attachments through a mail. The following example describes how a file can be attached to a mail: echo "Sending an attachment." | mutt -a backup.zip -s "attachment" local@domain.com

This command will send a mail to local@domain.com with the subject (-s) "attachment", the body text "Sending an

attachment.", containing the attachment (-a) backup.zip.

The LPRM command is used to remove a file from a print queue.

Answer option D is incorrect. The LPQ command reports the status of a print queue.

Answer option A is incorrect. The LPR command is used to submit a file for printing.

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

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.

Answer option A is incorrect. The chown command is used to change the user or group ownership of

the files specified with the command.

Answer option D is incorrect. The chgrp command is used to change only the group ownership of the

files specified with the command.

What is the chgrp command?

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 C is incorrect. There is no such command as chperm in Linux.

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 ls -al /root command lists all the files and directories, including hidden files in the /root

directory, in long listing format. /root is the root

user's home directory.

What is the ls command?

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:

ls -aR /home

Answer option B is incorrect. The ls command without arguments lists the file and directory names

in the current directory.

Answer option C is incorrect. The ls -s /root command shows the size of all files and directories (in blocks, not bytes) that reside in the /root directory.

Answer option D is incorrect. The ls -h /root command shows the size of files and directories in

"human readable format" (i.e. 19M, 3G, etc).

Answer option C is incorrect. The pdf2ps utility is used to convert a PDF file to a PostScript.

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.

Note: The swap file system cannot be mounted using the mount command.

Answer option D is incorrect. In Linux, the UMOUNT command is used to unmount a file system from its mount point.

Answer options A and B are incorrect. There are no such commands as attach and detach in Linux.

The /etc/group file contains group information. This file shows which users are members of which groups.

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.

The read permission allows a user to read a file. The content of a file can be seen by cat or less commands. When the read permission is set for a directory, it allows a user to read the names of files in the directory (but not to find out any other information about them including file type, ownership, size, etc.).

The write permission means that a user is permitted to write in a file. So, if a file has the write permission it can be edited and saved.

The execute permission grants a user the ability to execute a file. This permission must be set for executable binaries.

Answer option C is incorrect. If a file has the read permission, its contents can also be read not only the file name.

The lpq command views the content of a print queue.

Answer option D is incorrect. The lpr command sends a job to the queue to be printed.

Answer option A is incorrect. The lprm command removes a job from the queue.

Answer option B is incorrect. The lpstat -a command lists the configured printers.

The env command is used to list the environment variables that are set on a Linux computer.

The programs that run on a Linux computer are known as processes. When a user starts a program, a new process is created. This process runs within what is called an environment. A user can set parameters in this environment so that the running program can find the desired values. The following syntax is used to set a parameter to a variable:

VARIABLE=value

This would set a parameter by the name VARIABLE with the value that you provide. Some of the commonly used environment variables are HOME, PATH, PS1, etc.

Answer option B is incorrect. The rm command is used to delete files from a directory on a Linux computer.

Answer option C is incorrect. The ls command is used to list files on a Linux computer.

Answer option D is incorrect. The echo $shell command will provide the name of the current shell that a user is using.

You will use find -name foobar.png command to do case-senstive search for files named foobar.png.

What is the find command?

The find command can perform a search based on a variety of search limitations. It searches through one or more directory tree(s) of a filesystem, locating files based on some user-specified criteria. By default, find returns all files in the current working directory. Further, find allows a user to specify an action to be taken on each matched file.

Thus, it is an extremely powerful command for applying actions to many files.

The find command can be used with a wild card (*), but it works best when we know the name of the file or directory we are looking for.

The find command can search your system for files that comply with certain numeric criteria, such as the size of the file (-size), the number of links to the file (-links), the date of the last change to the files data (-mtime), or the date of the last time the file was read (-atime). All these criteria accept a numeric value. When a numeric value is provided to find, it looks for an exact match, more than the number, or less than the number.

Answer option B is incorrect. The find -iname foobar.png command will do case-insensitive search for files named foobar.png.

Answer option C is incorrect. The grep-name foobar.png is an invalid command.

What is the grep command?

The grep command is used to search for a specific pattern of text in a file. It helps administrators in searching large amounts of text for a certain error message or name.

Answer option A is incorrect. The locate -name foobar.png is an invalid command.

What is the locate command?

The locate command is used to search for matching files in a database that is usually updated daily by a cron job. On the forthcoming Linux operating systems, this command is usually replaced by the slocate command, which stores permissions as well as paths and thus prevents users from prying into directories. One more advantage of the locate command is that it matches against any part of a pathname, not just the file itself.

According to the scenario, you will use the wc -c file1.txt 2>error.txt command to accomplish the task. The 2> operator is an error redirector, which, while running a command, redirects the error (if it exists) on the specified file.

Answer options D and B are incorrect. The > or 1> redirector can be used to redirect the output of the wc -c file1.txt file to the error.txt file; however, you want to write the errors in the error.txt file, not the whole output.

Answer option A is incorrect. The >> operator will redirect the output of the command in the same manner as the > or 1> operator. Although the >> operator will not overwrite the error.txt file, it will append the error.txt file.

SELinux is an operating system based on Linux which includes Mandatory Access Control. The

SELinux provides Kernel-level security for Red Hat Enterprise Linux.

Answer options C, B, and A are incorrect. These are the features of SELinux.

What are the features of SELinux?

The features of SELinux are as follows:

SELinux provides Kernal-level security.

SELinux implements Mandatory access control (MAC) security in Red Hat Enterprise Linux.

SELinux assigns every file and process on the system a context, identifying its type and purpose.

SELinux enforces a policy that dictates which actions a given type of process may take on a given type of file

SELinux applies to all users, including root.

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.

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.

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 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 w command displays currently logged-in users and their tasks.

Answer option C is incorrect. The whoami command displays the user name of the current user.

Answer option D is incorrect. The who command displays currently logged-in users. It does not display their tasks.

Answer option B is incorrect. The finger command displays information on system users.

If there is no free space on the hard disk drive, users will not be able to write on it. To prevent this issue from happening again, you should track the amount of free space on the hard disk. By doing so, you can take necessary actions before the actual problem arises.

Answer option B is incorrect. Even if users save their important files, the hard disk drive will still become full sooner or later.

Answer option A is incorrect. Dedicating a hard disk drive for users to save their files will not prevent the drive from becoming full.

Answer option D is incorrect. The shortage of RAM is not the issue in this scenario.

This command will search for files with a size of over 50 megabytes. The -size option tells find to search files according to the size of files, and

+50M will tell the find command to search files over 50 megabytes.

Answer option C is incorrect. This command will search for files with a size of exactly 50 megabytes.

Answer option B is incorrect. This command will search for files with a size of less than 50 megabytes.

Answer option D is incorrect. - must be prefixed with size, otherwise shell will not recognize this command, and display an error message.

You can use the tr command to convert all lowercase letters of a text file to uppercase. The tr

command is used to translate, squeeze, and/or delete characters from standard input, writing to standard output. If you want to change all lowercase letters to uppercase, you will use the tr

[a-z] [A-Z] command.

Answer options B, A, and D are incorrect. The cat, tac, and less commands are used to display the output of the text file on the screen. These commands cannot translate the text from one form to another.

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 lprm command is used to remove the print jobs that have been queued for printing. If no arguments are supplied, the current job on the default destination is cancelled. The command syntax for the lprm command is as follows:

lprm [-E] [-U username] [-h server[:port]] [-P destination[/instance]] [-] [job ID(s)]

where,

When 1 is added as a prefix to the permission set, it adds the sticky bit to the file permission.

Therefore, in order to accomplish the task, you will have to run the following command: chmod 1744 report

What is sticky bit?

The sticky bit is a part of a permission set applied to files or folders. The sticky bit prevents others from deleting files from a folder. When the sticky bit is set on a directory, only the owner or root can unlink (delete) or rename the files in that directory. Without the sticky bit, anyone who is able to write to the directory can delete or rename the files.

Answer option A is incorrect. This will set SGID to the file permission.

Answer option B is incorrect. This will set SUID to the file permission.

Answer option C is incorrect. Although this will add a sticky bit to the file permission, it will also set SGID and SUID to the file permission.

What are SUID and SGID?

Set user ID (SUID) and Set group ID (SGID) are used to set a file to run as something other than the standard. Normally, when a file is executed, it runs as the user who invokes it. Setting a file to SUID or SGID simply requires adding an extra digit to the permissions. Technically, if no digit is used, it assumes a leading 0.

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.

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 less command is most useful for viewing large files. The less command displays the output of a file one page at a time. Viewing large files through cat may take more time to scroll pages, so it is better to use the less command to see the content of large files.

Answer option B is incorrect. The cat command is also used to view the content of a file, but it is most useful for viewing short files.

Answer option A is incorrect. The cp command is used to copy files and directories from one location to another.

Answer option D is incorrect. The touch command is not used to view the content of a file. It is used to create empty files or to update file timestamps.

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 lastb command is used to view failed login attempts on a user account.

What is the lastb command?

The lastb command is used to view bad login attempts. The command searches in reverse order through the database file named /var/adm/btmp in order to display the required information.

Answer option C is incorrect. The lastlog command reports the most recent logins of all users or of a given user.

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

The inode table contains the last access time, last modification time as well as the last inode change time of a file.

What type of data is stored in an inode table?

An inode table contains a list of all files in an ext2 and ext3 filesystem. An inode ( index node) is an entry in the table, containing information about a file (the metadata). Some important data stored in the inode table are as follows:

The file type (regular file, directory, etc.)

File permissions

Link count: The number of file names associated with the inode number.

The user ID number of file owner and the group ID number of the associated group.

Timestamps, including last access time, last modification time, and last inode change time.

Location of the data on the hard disk.

Answer options D, B, and A are incorrect. The inode table contains all these information, the file type, file permissions on the specified file, location of data on the hard disk.

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.

In order to accomplish the task, you will have to execute the following command: find /-perm -4000

This command will search the current directory and its sub-directories for all the files on which SUID has been set.

Answer options C and B are incorrect. The ls command is used to list all files in the current directory and its subdirectory.

Answer option A is incorrect. This will find all the files on which SGID is set.

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

The following directories cannot be separated from the root filesystem:

/lib

/dev

/etc

/sbin

/bin

Answer option D is incorrect. /var can be separated from the root filesystem. Such filesystems are known as optional filesystems. Some of the optional filesystems are as follows:

/var

/usr

/opt

/home