LFCS Certification Shell Scripting and Automation 2

Question 1

What does the command substitution syntax $(command) do in a bash script?

Accepted Answer

Captures the stdout output of a command and inserts it inline

Answer

Runs the command in the background as a subshell

Answer

Defines a new subshell environment variable

Answer

Redirects command output to /dev/null silently

Question 2

In a bash script, how do you correctly access the third positional argument passed to the script?

Accepted Answer

$3

Answer

$0

Answer

$2

Answer

$arg3

Question 3

What does the `shift` command do when called in a bash script?

Accepted Answer

Shifts all positional parameters left by one, dropping $1

Answer

Moves script execution to another function definition

Answer

Changes the current working directory to the parent

Answer

Reverses the order of all positional parameters

Question 4

Which test expression correctly checks that a path exists and is a regular file (not a directory)?

Accepted Answer

[ -f filename ]

Answer

[ -d filename ]

Answer

[ -e filename ]

Answer

[ -r filename ]

Question 5

What is the key distinction between the `=` operator and `-eq` in bash conditional tests?

Accepted Answer

`=` compares strings lexicographically and `-eq` compares integers numerically

Answer

`=` is for arithmetic comparisons and `-eq` is for string comparisons

Answer

They are fully interchangeable inside single brackets

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`-eq` requires double brackets [[ ]] while `=` works in both

Question 6

Which syntax correctly defines a bash function named `backup`?

Accepted Answer

backup() { commands; }

Answer

def backup() { commands; }

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backup: function { commands; }

Answer

sub backup { commands; }

Question 7

What is the effect of adding `set -e` at the top of a bash script?

Accepted Answer

Causes the script to exit immediately when any command returns a non-zero status

Answer

Enables extended glob patterns for filename matching

Answer

Sources environment variables from an external file

Answer

Enables debug mode, printing each command before it runs