Advanced Shell Scripting and Automation in Linux

1. Which command substitution syntax is preferred in modern bash scripts?

`command`

$(command)

{command}

[command]

2. What is the primary advantage of using functions in shell scripts?

They execute faster than inline code

They allow code reuse and improve script organization

They automatically handle all errors

They eliminate the need for variable declarations

3. In bash, what does the 'declare -r' command do?

Declares a variable as read-only

Declares a variable as recursive

Declares a variable for remote access

Declares a variable with restricted scope

4. Which command is used to schedule scripts to run at specific times in Linux?

Scheduler

Cron or at

Systemd-timer only

Clockd

5. What does the 'read' command accomplish in a bash script?

Reads and executes commands from a file

Reads input from stdin into a variable

Reads file permissions and displays them

Reads environment variables from the system

6. In bash parameter expansion, what does ${variable:-default} do?

Assigns a default value permanently to the variable

Uses the default value if variable is unset or null

Removes the variable and uses default

Creates a new variable with a default suffix

7. What is the purpose of the 'trap' command in bash scripting?

Catches and handles errors in command execution

Sets up signal handlers to execute code on specific signals

Prevents unauthorized access to the script

Traps variables to prevent modification

8. In bash, what does the 'set -e' command do in a script?

Enables debug output for every command

Exits the script immediately if any command fails

Sets environment variables to read-only

Enables error handling for all subshells

9. What does the grep -E flag enable in text pattern matching?

Extended regular expressions for complex patterns

Error reporting mode

Exact match mode only

Encoding detection for special characters

10. What is the difference between $* and $@ in a bash script?

$* expands all arguments as separate words; $@ expands as a single string

$@ expands all arguments as separate words; $* expands as a single string

They are identical and interchangeable

$* includes only positional arguments; $@ includes all variables

11. Which regex pattern matches one or more occurrences of the preceding character?

*

?

+

{1,}

12. In bash, what does the && operator do when chaining commands?

Runs both commands in parallel

Executes the second command only if the first succeeds

Runs commands in a subshell

Pipes output from the first to the second

13. What does [[ ]] provide compared to [ ] in bash conditional statements?

Faster execution speed only

Support for regex matching and word splitting prevention

Compatibility with older shell versions

Access to external command evaluation

14. Which loop construct is best for iterating over an array in bash?

While loop with counter

Until loop with condition

For loop with array expansion ${array[@]}

Do-while loop with break statement

15. What is the purpose of the IFS variable in bash?

It stores the internal field separator used for word splitting

It defines the input file system type

It sets the interactive frame size for terminals

It enables input filtering and sanitization

16. In a bash script, how do you define a function that accepts parameters?

Function_name() { echo $1 $2; }

Function function_name(param1, param2) { echo $1; }

Define function_name { param1 param2; }

Function_name := function(x, y) { return $1; }

17. What does the -x flag do when running a bash script?

Executes the script in the background

Enables debug mode and prints commands before execution

Prevents the script from modifying files

Requires explicit user confirmation for each command

18. In bash, what does the $? variable represent after a command executes?

The process ID of the last background process

The exit status code of the last executed command

The number of arguments passed to the script

The current working directory path

19. How do you redirect both stdout and stderr to the same file in bash?

Command > file 2>&1

Command &> file or command > file 2> file

Command >> file 2>> file

Command 2>&1 > file

20. Which sed command replaces the first occurrence of a pattern on each line?

Sed 's/pattern/replacement/'

Sed 's/pattern/replacement/g'

Sed 's/pattern/replacement/1'

Sed 'g/pattern/replacement/'

General Linux Advanced Shell Scripting and Automation Quiz