Quiz Module 6 - Shell Scripting

Instructions

This quiz contains 30 multiple-choice questions to validate your understanding of Module 6.

Tip: Answer each question before revealing the answer. The answers are hidden just after each question.

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Question 1

What is the standard shebang for a Bash script?

1. #!/bin/sh

2. #!/bin/bash

3. #!/usr/bin/bash

4. #!/bash

See explanation

Correct answer: #!/bin/bash

Explanation: The shebang #!/bin/bash indicates that the script should be executed with Bash. It must be on the first line of the script. Example: #!/bin/bash followed by a blank line then the code.

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Question 2

How to make a script executable?

1. chmod +r script.sh

2. chmod +x script.sh

3. chmod +w script.sh

4. chmod 644 script.sh

See explanation

Correct answer: chmod +x script.sh

Explanation: chmod +x script.sh adds execution permission to the script. You can then execute it with ./script.sh or bash script.sh. chmod 755 script.sh does the same thing.

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Question 3

How to declare a variable in Bash?

1. var = "value"

2. var="value"

3. var: "value"

4. set var = "value"

See explanation

Correct answer: var="value"

Explanation: In Bash, you declare a variable with var="value" (no spaces around the =). To use the variable: $var or ${var}. To display it: echo $var.

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Question 4

Which command schedules a recurring task in Linux?

1. schedule

2. cron

3. timer

4. task

See explanation

Correct answer: cron

Explanation: cron is the daemon that runs scheduled tasks. crontab is the command to manage cron tasks. Tasks are defined in crontab files with a special syntax.

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Question 5

Which command edits a user's cron tasks?

1. cronedit

2. crontab -e

3. editcron

4. cron -e

See explanation

Correct answer: crontab -e

Explanation: crontab -e opens the editor to modify the current user's cron tasks. crontab -l lists tasks, crontab -r removes all tasks. Tasks are stored in /var/spool/cron/crontabs/username.

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Question 6

What is the correct syntax of a crontab line?

1. minute hour day month command

2. minute hour day month day-of-week command

3. hour day month command

4. day month year command

See explanation

Correct answer: minute hour day month day-of-week command

Explanation: Crontab format: minute hour day month day-of-week command. Examples: 0 * * * * (every hour), 0 0 * * * (midnight every day), */5 * * * * (every 5 minutes). Days of the week: 0-7 (0 and 7 = Sunday).

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Question 7

Which crontab syntax runs a task every hour?

1. 0 0 * * *

2. 0 * * * *

3. ---

4. 0 1 * * *

See explanation

Correct answer: 0 * * * *

Explanation: 0 * * * * means: minute 0 of every hour, every day, every month, every day of the week = every hour at minute 0. 0 0 * * * = midnight every day. * * * * * = every minute.

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Question 8

Which crontab syntax runs a task every day at midnight?

1. 0 0 * * *

2. 0 * * * *

3. • 0 * * *

4. 0 0 0 * *

See explanation

Correct answer: 0 0 * * *

Explanation: 0 0 * * * means: minute 0, hour 0 (midnight), every day, every month, every day of the week = every day at midnight. It's very common for daily backups.

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Question 9

Which command lists a user's cron tasks?

1. crontab -s

2. crontab -l

3. crontab -v

4. cron -l

See explanation

Correct answer: crontab -l

Explanation: crontab -l lists the current user's cron tasks. crontab -l -u username lists another user's tasks (requires root). crontab -e edits, crontab -r removes all tasks.

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Question 10

Which control structure allows executing conditional code in Bash?

1. if-then

2. if-then-else

3. when

4. condition

See explanation

Correct answer: if-then-else

Explanation: The if-then-else structure allows executing conditional code. Syntax: if [ condition ]; then commands; else commands; fi. Example: if [ $var -eq 10 ]; then echo "Equal"; fi.

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Question 11

Which loop iterates over a list in Bash?

1. while

2. for

3. loop

4. foreach

See explanation

Correct answer: for

Explanation: The for loop iterates over a list. Syntaxes: for var in list; do commands; done or for ((i=1; i<=10; i++)); do commands; done. Example: for file in *.txt; do echo $file; done.

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Question 12

Which loop executes code as long as a condition is true?

1. while

2. for

3. loop

4. until

See explanation

Correct answer: while

Explanation: The while loop executes code as long as a condition is true. Syntax: while [ condition ]; do commands; done. until does the opposite (as long as the condition is false). Beware of infinite loops!

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Question 13

Which variable contains the return code of the last command?

1. $RETURN

2. $?

3. $STATUS

4. $EXIT

See explanation

Correct answer: $?

Explanation: $? contains the return code of the last command. 0 = success, non-zero = error. Example: command; if [ $? -eq 0 ]; then echo "Success"; fi. You can also use directly: if command; then ....

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Question 14

Which variable contains the number of arguments passed to the script?

1. $ARGS

2. $#

3. $COUNT

4. $N

See explanation

Correct answer: $#

Explanation: $# contains the number of arguments passed to the script. $1, $2, etc. contain individual arguments. $0 contains the script name. $@ contains all arguments.

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Question 15

Which variable contains the first argument passed to the script?

1. $0

2. $1

3. $ARG

4. $FIRST

See explanation

Correct answer: $1

Explanation: $1 contains the first argument, $2 the second, etc. $0 contains the script name. $@ contains all arguments. Example: ./script.sh arg1 arg2 → $1="arg1", $2="arg2".

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Question 16

Which command creates a function in Bash?

1. def function_name()

2. function_name() followed by commands in braces

3. function function_name()

4. create function_name()

See explanation

Correct answer: function_name() followed by commands in braces

Explanation: Syntax to create a function: function_name() { commands; } (with braces around the commands). You can also use function function_name { commands; }. To call: function_name or function_name arg1 arg2. Note: Braces are necessary to delimit the function body.

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Question 17

Which file contains system cron tasks (for all users)?

1. /etc/cron

2. /etc/crontab

3. /var/cron/tab

4. /usr/cron/tab

See explanation

Correct answer: /etc/crontab

Explanation: /etc/crontab contains system cron tasks. Similar format but with a user field: minute hour day month day-of-week user command. The directories /etc/cron.d/, /etc/cron.hourly/, /etc/cron.daily/, etc. also contain system tasks.

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Question 18

Which directory contains scripts executed daily by cron?

1. /etc/cron.daily

2. /etc/cron.daily

3. /var/cron/daily

4. /usr/cron/daily

See explanation

Correct answer: /etc/cron.daily

Explanation: /etc/cron.daily/ contains scripts executed daily. Similar: /etc/cron.hourly/, /etc/cron.weekly/, /etc/cron.monthly/. These scripts are executed by anacron or run-parts.

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Question 19

Which command tests if a file exists in Bash?

1. test -e

2. [ -f file ] or test -f file

3. exists file

4. file -e file

See explanation

Correct answer: [ -f file ] or test -f file

Explanation: [ -f file ] tests if a file exists and is a regular file. Other tests: [ -d file ] (directory), [ -e file ] (exists), [ -r file ] (readable), [ -w file ] (writable), [ -x file ] (executable).

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Question 20

Which command reads user input in a Bash script?

1. input

2. read

3. get

4. ask

See explanation

Correct answer: read

Explanation: read variable reads a line from standard input and stores it in the variable. Examples: read name, read -p "Enter your name: " name (with prompt), read -s password (hide input).

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Question 21

Which structure allows making a multiple choice in Bash?

1. if-elif-else

2. case-esac

3. switch

4. select

See explanation

Correct answer: case-esac

Explanation: case allows making a multiple choice. Syntax: case $var in pattern1) commands;; pattern2) commands;; *) commands;; esac. More readable than multiple if-elif for many choices.

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Question 22

Which crontab syntax runs a task every 5 minutes?

1. 5 * * * *

2. */5 * * * *

3. 0-5 * * * *

4. 5,10,15 * * * *

See explanation

Correct answer: */5 * * * *

Explanation: */5 * * * * means every 5 minutes. The */5 means "every value divisible by 5". 5 * * * * = only at minute 5 of every hour. 5,10,15 * * * * = at minutes 5, 10, and 15.

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Question 23

Which variable contains the current process's PID?

1. $PID

2. $$

3. $PROCESS

4. $CURRENT

See explanation

Correct answer: $$

Explanation: $$ contains the current shell process's PID. Useful for creating unique temporary files: tempfile="/tmp/script.$$". $PPID contains the parent process's PID.

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Question 24

Which command redirects error output to a file?

1. command > error.log

2. command 2> error.log

3. command >> error.log

4. command error> error.log

See explanation

Correct answer: command 2> error.log

Explanation: 2> redirects error output (stderr, file descriptor 2). > redirects standard output (stdout, file descriptor 1). 2>&1 redirects stderr to stdout. &> redirects both to a file.

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Question 25

Which command redirects both standard and error output to a file?

1. command > file 2> file

2. command &> file or command > file 2>&1

3. command >> file

4. command | file

See explanation

Correct answer: command &> file or command > file 2>&1

Explanation: command &> file redirects stdout and stderr to the file. Equivalent to command > file 2>&1. The order is important: 2>&1 must come after > file to redirect stderr to the same place as stdout.

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Question 26

Which command creates an array in Bash?

1. array = (1 2 3)

2. array=(1 2 3)

3. array: 1 2 3

4. declare array = (1 2 3)

See explanation

Correct answer: array=(1 2 3)

Explanation: Syntax to create an array: array=(1 2 3) or array=("one" "two" "three"). To access: ${array[0]}, ${array[1]}, etc. ${array[@]} contains all elements. ${#array[@]} = number of elements.

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Question 27

Which crontab syntax runs a task every Monday at 9:00 AM?

1. 0 9 * * 0

2. 0 9 * * 1

3. 9 0 * * 1

4. 0 9 1 * *

See explanation

Correct answer: 0 9 * * 1

Explanation: 0 9 * * 1 = minute 0, hour 9, every day, every month, Monday (1). Days of the week: 0 or 7 = Sunday, 1 = Monday, 2 = Tuesday, ..., 6 = Saturday.

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Question 28

Which command exits a function with a return value?

1. exit

2. return

3. break

4. stop

See explanation

Correct answer: return

Explanation: return exits a function with a return code. return 0 = success, return 1 = error. exit exits the entire script. break exits a loop. return without an argument returns the last command's code.

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Question 29

Which command exits a script with a return code?

1. exit

2. return

3. quit

4. stop

See explanation

Correct answer: exit

Explanation: exit exits the script with a return code. exit 0 = success, exit 1 (or other non-zero) = error. If no code is specified, it uses the last command's code. return only works in functions.

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Question 30

Which command views cron task logs on Ubuntu 24.04?

1. /var/log/cron

2. journalctl -u cron or grep CRON /var/log/syslog

3. /var/log/crontab

4. cronlog

See explanation

Correct answer: journalctl -u cron or grep CRON /var/log/syslog

Explanation: On Ubuntu 24.04, cron logs are in systemd logs. journalctl -u cron shows the cron service logs. You can also search in /var/log/syslog: grep CRON /var/log/syslog. Logs show executions and errors of cron tasks.

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Quiz Result

Congratulations on completing the Module 6 quiz!

Score:

• 25-30 correct answers: Excellent! You master Bash scripting and cron.
• 20-24 correct answers: Very good! Review the concepts where you had difficulties.
• 15-19 correct answers: Good! Review the chapters on scripting and cron.
• Less than 15: Recommended to review the module before continuing.

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Next Steps

Now that you have validated your knowledge:

Module 7: Networking and Configuration
Practical Labs: Practice scripting and cron with Module 6 labs

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Quiz created on: December 2024 - Tested on Ubuntu 24.04