Linux+ Basic Bash Scripting Flashcards

Which operator is used to append output to an existing file in Bash?

Answer: >>

The >> operator appends output to a file without overwriting its existing contents.

What does the special variable $? represent in Bash?

Answer: The exit status of the last command

$? holds the exit status of the most recently executed command, where 0 typically means success.

Given the script: `for i in {1..5}; do echo $i; done`, what is the output?

Answer: Prints 1 through 5 each on a new line

Brace expansion {1..5} generates the sequence 1 2 3 4 5, so the loop prints each number on its own line.

Which command inside a Bash function returns a value to the caller?

Answer: return

The return statement exits a function and sets its exit status code, which the caller can read via $?.

What is the purpose of the `read` command in a Bash script?

Answer: Reads a line of input from stdin into a variable

The read command pauses execution and stores a line of user input (or piped input) into one or more variables.

In Bash, what does `[ -d /etc ]` test?

Answer: Whether /etc exists and is a directory

The -d flag in a test expression returns true if the given path exists and is a directory.

Which shebang line correctly specifies Bash as the interpreter for a script?

Answer: #!/usr/bin/env bash

#!/usr/bin/env bash is the portable shebang that finds bash via the PATH, recommended over hardcoded paths.