Linux+ Basic Bash Scripting Flashcards

Which command is used to define a function in Bash?

Answer: function myfunc() {} or myfunc() {}

Bash accepts both the function keyword form and the compact name() {} form for defining functions.

What does the `-z` flag test in a Bash conditional?

Answer: Whether a string is empty (zero length)

[ -z "$var" ] returns true when the string variable is empty (has zero length).

Given `array=(a b c d)`, what does `${#array[@]}` return?

Answer: The number of elements (4)

${#array[@]} returns the count of elements in the array, which is 4 for this example.

What is a heredoc used for in Bash scripting?

Answer: Passing a multi-line block of text to a command as stdin

A heredoc (<<DELIMITER) allows embedding a multi-line string literal directly in a script as standard input to a command.

Which statement correctly breaks out of a loop early in Bash?

Answer: break

The break statement terminates the innermost loop and continues execution after it.

In command substitution, what is the difference between backticks and $(...)?

Answer: $(...) is preferred because it supports nesting and is more readable

$(...) is the modern preferred form because it can be nested and is easier to read than backticks.

Which variable holds the name of the currently executing Bash script?

Answer: $0

$0 contains the name or path of the script (or shell) as it was invoked.