LFCS Certification Shell Scripting and Automation 3

Question 1

Which redirection syntax correctly sends both stdout and stderr to a file named output.log?

Accepted Answer

command > output.log 2>&1

Answer

> output.log redirects stdout, then 2>&1 redirects stderr to the same file descriptor as stdout, capturing both streams.

Question 2

What is the primary purpose of the `trap` command in a bash script?

Accepted Answer

To catch signals or errors and run a specified handler command

Answer

trap registers a handler (command or function) to execute when the script receives a specified signal such as EXIT, INT, or ERR.

Question 3

What is a here-document (heredoc) in bash scripting?

Accepted Answer

A block of multi-line text passed as stdin to a command, delimited by a marker word

Answer

A heredoc uses << MARKER ... MARKER syntax to feed multiple lines of text as standard input to a command without needing a temporary file.

Question 4

What is the purpose of the `getopts` built-in in a bash script?

Accepted Answer

Parses short command-line options (e.g., -v, -f) passed to the script

Answer

getopts processes POSIX-style single-character options and their optional arguments in a portable, standards-compliant way.

Question 5

Which bash syntax correctly performs integer arithmetic and stores the result in the variable `result`?

Accepted Answer

result=$((num1 + num2))

Answer

The $(( )) arithmetic expansion evaluates integer expressions natively in bash without invoking an external command.

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