Question 1

To negate a set in a regular expression pattern, which character is used?

Accepted Answer

The caret (^) character is used to negate a set in a regular expression pattern. For example, [^a-z] would match any character that is not a lowercase letter.

Question 2

In a bash script, which of the following is the most common way to send output to the screen?

Accepted Answer

The "echo" command is the most common way to send output to the screen in a bash script. It allows you to print text or variables to the terminal window. "Write" is used to send a message to another user via a terminal, "send" is not a valid command, and "print" is not typically used in bash scripts.

Question 3

In regular expressions, to what does greedy vs. lazy refer?

Accepted Answer

The answer of In regular expressions, to what does greedy...

Question 4

Why is iostat not needed on an Arista switch?

Accepted Answer

The answer of Why is iostat not needed on an...

Question 5

Which of the following is true when using the mv command to move a file to a new location on the same filesystem?

Accepted Answer

When using the mv command to move a file to a new location on the same filesystem, only the directory entry needs to be updated which is a very fast process. Therefore, option D is the correct answer.

Question 6

Which native system commands can be used to get help on a standard Linux system?

Accepted Answer

The "man" command is used to get detailed help on almost any topic or command on a Linux system. It stands for "manual" and provides detailed descriptions of command options and syntax. Option "-h" or "--help" can also provide some basic help, but "man" typically provides more comprehensive information. Options "A" and "D" are not native system commands and require an internet connection. Option "B" is also a native system command, but may not always be available or provide as detailed information as "man".

Question 7

What is the two-character sequence at the top of scripts, which tells the kernel what interpreter to use, called?

Accepted Answer

The two-character sequence at the top of scripts, which tells the kernel what interpreter to use, is called a shebang or a hashbang. It is represented by the characters #! and is typically followed by the path to the interpreter (e.g. #!/bin/bash for a Bash script).

Question 8

Which of these is true about the MBR?

Accepted Answer

The MBR (Master Boot Record) is not OS-specific, meaning it is stored on the first sector of a hard drive and can be accessed by any operating system. It contains the partition table, which shows the layout of the disk and enables the system to boot. However, it does not contain the kernel and is not always stored in memory. It also does not require the Volume Boot Record, but the VBR typically follows the MBR in the boot process.

Question 9

RHEL is a popular distribution from which core tree?

Accepted Answer

The answer of RHEL is a popular distribution from which...

Question 10

Which special device provides a place for redirecting unneeded data?

Accepted Answer

/dev/null is a special device file that discards all the data written to it and provides a place for redirecting unneeded data. In other words, any data written to /dev/null is essentially thrown away and lost.

Question 11

What does the ctime of a file indicate?

Accepted Answer

The ctime of a file indicates the time when the file's metadata was last changed, such as its permissions or ownership. It does not necessarily indicate the time when the file was created or when its contents were last modified. Therefore, the correct choice is B) Change time.

Question 12

Which of these help documentation systems are installed on Arista switches?

Accepted Answer

The "man" command is used to display the manual pages for commands and system calls on Arista switches.

Question 13

Which of the following commands is most likely to cause you to need to restore from backup?

Accepted Answer

The command "rm -rf" is used to forcibly remove files and directories, including their contents, without asking for confirmation. If used improperly, this command can accidentally delete important files or even the entire system, requiring a restore from backup. The other commands listed are unlikely to cause issues that would require a backup restore.

Question 14

The standard input file descriptor defaults to what?

Accepted Answer

The standard input file descriptor defaults to the null device, which is a special file that discards all data written to it.

Question 15

What does grep stand for?

Accepted Answer

grep stands for "global regular expression print," which refers to its capability to search for and print out lines that match a given pattern using regular expressions.

Question 16

If there are three arguments on the command line to a bash script, what will be the contents of $# builtin variable?

Accepted Answer

The $# builtin variable contains the number of arguments passed to the script. In this case, since there are three arguments, the value of $# will be 3.

Question 17

In bash scripting, which of the following comparison operators are used on strings?

Accepted Answer

The == operator is used to compare two strings for equality in bash scripting. The other options are used for comparing integers or checking file attributes.

Question 18

What will the permissions of a regular file with octal mode 755 look like in the output of the 1s command?

Accepted Answer

The octal mode 755 represents the following permissions:- User: read, write, execute (rwx)- Group: read, execute (r-x)- Others: read, execute (r-x)In the output of the ls command, this will be represented as "-rw-r-r--".

Question 19

If one or more CPUs in a system is extremely busy (less than 25% idle) but the run queue is relatively low, what might the system need to improve performance?

Accepted Answer

More CPUs would help balance the load and reduce the workload on the busy CPUs.

Question 20

On an Arista switch, where in the filesystem is the flash drive mounted?

Accepted Answer

The flash drive is typically mounted at /mnt on an Arista switch.

Exam 2: Arista Linux Essentials Exam