Lpi 102-500 LPI Level 1 Online Training

Question #81

Fill in Blanks

The ________ command is used to add a group to the system.

Question #82

Which command will set the local machine’s timezone to UTC?

A . cat UTC > /etc/timezone
B . ln -s /usr/share/zoneinfo/UTC /etc/localtime
C . date –timezone=UTC
D . mv /usr/timezone/UTC /etc

Question #83

Which command should be added to /etc/bash_profile to change the language of messages from an internationalised program to Portuguese (pt)? (Select TWO correct answers)

A . export LANGUAGE="pt"
B . export MESSAGE="pt"
C . export LANG="pt"
D . export LC_MESSAGES="pt"
E . export ALL_MESSAGES="pt"

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Question #84

A user was not given permission to use the CRON scheduling system.

What file needs to be modified to provide that access? (Please specify the full path to the file)

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Question #85

Which commands can you use to change a user’s account aging information? (Choose THREE correct answers.)

A . usermod
B . passwd
C . chattr
D . chage
E . chsh

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Correct Answer: A, B, D
A, B, D

Explanation:

The commands that can be used to change a user’s account aging information are: usermod: this command can modify various user account properties, including the password expiration date, the account expiration date, the minimum and maximum password age, the password warning period, and the password inactivity period. To use this command, you need to specify the option and the value for the property you want to change, followed by the username. For example, to set the password expiration date for the user test to February 11, 2022, you can run: usermod -e 2022-02-11 test

To view the current account aging information for a user, you can use the -l option with the usermod command. For example, to view the information for the user test, you can run:

usermod -l test

passwd: this command can change the password of a user account, as well as some password aging options. To use this command, you need to specify the username and the option for the property you want to change. For example, to change the password of the user test, you can run: passwd test

To set the maximum password age for the user test to 90 days, you can run:

passwd -x 90 test

To view the current password aging information for a user, you can use the -S option with the passwd command. For example, to view the information for the user test, you can run: passwd -S test

chage: this command can change the user password expiry and aging information, such as the password expiration date, the account expiration date, the minimum and maximum password age, the password warning period, and the password inactivity period. To use this command, you need to specify the option and the value for the property you want to change, followed by the username. For example, to set the account expiration date for the user test to February 11, 2022, you can run: chage -E 2022-02-11 test

To view the current account aging information for a user, you can use the -l option with the chage command. For example, to view the information for the user test, you can run: chage -l test

The other options are incorrect because:

chattr: this command can change the file attributes on a Linux file system, such as making a file immutable, append-only, or undeletable. It has nothing to do with user account aging information. chsh: this command can change the login shell of a user account, such as bash, zsh, or ksh. It has nothing to do with user account aging information.

Reference: How to Manage User Password Expiration and Aging in Linux – Tecmint Use the Chage Command in Linux

How to set user password expirations on Linux | Enable Sysadmin

How to change password and account expiry options on Linux using chage – Linux Tutorials – Learn Linux Configuration 3 ways to change user password expiration date in Linux – howtouselinux

Question #86

Why is /etc/shadow not world readable if the passwords are stored in an encrypted fashion?

A . The encrypted passwords are still subject to brute force attacks.
B . This is just for historical reasons.
C . There is other information in the file that needs to be kept secret.
D . The passwords can be decrypted by anyone with root access.

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Question #87

Of the ways listed, which is the best way to temporarily suspend a single user’s ability to interactively login?

A . Add the user name to /etc/nologin.
B . Change the user’s password.
C . Change the user name in /etc/passwd.
D . Use change to expire the user account.
E . Place the command logout in the user’s profile.

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Correct Answer: D
D

Explanation:

The best way to temporarily suspend a single user’s ability to interactively login is to use the chage command to expire the user account. The chage command can modify the expiration date of a user account, which is stored in the /etc/shadow file. By setting the expiration date to a past date, the user account will be locked and the user will not be able to login. This method is temporary because the expiration date can be changed again to a future date or removed to unlock the user account. For example, to expire the user account linuxconfig, we can use the following command: # chage -E 0 linuxconfig

This will set the expiration date to January 1, 1970, which is the epoch date.

To check the expiration date of a user account, we can use the -l option:

To remove the expiration date of a user account, we can use the -E option with an empty argument:

# chage -E "" linuxconfig

The other options are either invalid or not recommended. Adding the user name to /etc/nologin will not work, because /etc/nologin is a file that contains a message to be displayed to users who try to login when the system is down for maintenance. Changing the user’s password is not a good idea, because it will affect the user’s authentication and may cause security issues. Changing the user name in /etc/passwd will also affect the user’s authentication and may cause inconsistencies with other files and services. Placing the command logout in the user’s profile will not prevent the user from logging in, but only log them out immediately after login, which is not very elegant or secure.

Reference: 1: How to disable user login with Linux nologin – LinuxConfig.org 2: Disable a user’s login without disabling the account – Unix & Linux Stack Exchange 3: How to Block or Disable Normal User Logins in Linux? – GeeksforGeeks 4: How to Disable User Logins on Linux | Baeldung on Linux 5: How to Disable a User in Linux – Linux Nightly 6: How to deactivate or disable a user account in Ubuntu 20.04 LTS – Vitux 7: chage(1) – Linux manual page

Question #88

Which TWO statements about crontab are true?

A . Every user may have their own crontab.
B . Changing a crontab requires a reload/restart of the cron daemon.
C . The cron daemon reloads crontab files automatically when necessary.
D . hourly is the same as "0 * * * *".
E . A cron daemon must run for each existing crontab.

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Question #89

Which crontab entry could be used to set the system time at regular intervals?

A . 1 0 * * * date $d $t $24
B . 1 0 * * * ntpdate ntp1.digex.net
C . 1 0 * * * date ntp1.digex.net
D . 1 0 * * * runcron date ntp1.digex.net
E . 1 0 * * * settime $d $t $24

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Question #90

Which of the following commands can be used to convert text files in one character encoding to another character encoding?

A . cat
B . convert
C . dd
D . iconv
E . utf2utf

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Correct Answer: D
D

Explanation:

The command that can be used to convert text files in one character encoding to another character encoding is:

iconv: this command can convert text files from one form of encoding to another, such as UTF-8, ISO-8859-1, ASCII, etc. To use this command, you need to specify the input encoding, the output encoding, and the file name. For example, to convert a file named input.txt from ISO-8859-1 to UTF-8, you can run:

iconv -f ISO-8859-1 -t UTF-8 input.txt

The output will be printed to the standard output, which can be redirected to another file or piped to another command. You can also use the -o option to specify the output file name. For example, to convert the same file and save the output to output.txt, you can run: iconv -f ISO-8859-1 -t UTF-8 -o output.txt input.txt

To list all the supported encodings, you can use the -l option. For example, to see all the encodings

that start with UTF, you can run:

iconv -l | grep UTF

The iconv command is part of the GNU libc package and is available on most Linux systems. The full

path of the command is /usr/bin/iconv.

The other options are incorrect because:

cat: this command can concatenate and print files to the standard output, but it does not perform any encoding conversion. It can be used to display the contents of a text file, but it will not change the encoding of the file.

convert: this command can convert image files from one format to another, such as PNG, JPEG, GIF, etc. It is part of the ImageMagick suite of tools and is not related to text encoding conversion.

dd: this command can copy and convert data from one source to another, such as files, devices, or pipes. It can perform some conversions, such as changing the case of letters, swapping bytes, or converting between ASCII and EBCDIC, but it does not support common text encodings such as UTF-8 or ISO-8859-1.

utf2utf: this is not a valid command on Linux. There is no such tool that can convert between different UTF encodings.

Reference: How to Convert Files to UTF-8 Encoding in Linux – Tecmint

Best way to convert text files between character sets? – Stack Overflow

how to change encoding of a text file without openning the file in shell program – Stack Overflow HowTo: Check and Change File Encoding In Linux – ShellHacks

How to change character encoding of a text file on Linux – Xmodulo

Topic 4, Essential System Services