Which characters, if used, indicate you should use single quotes to prevent shell expansion?

• A. <, >
• B. $, `, \
• C. ', "
• D. ~, %

Answer: (B)

When you want to pass characters to the shell without having them be interpreted or expanded, you focus on metacharacters that trigger such processing. The dollar sign starts parameter and command-substitution expansions, so a literal dollar sign would be expanded if left unquoted. The backtick is a classic command-substitution delimiter, causing the shell to run a command and replace it with its output. The backslash acts as an escape character, removing the special meaning of the next character; without quoting, that escaping can change how the following text is interpreted. Using single quotes around the string tells the shell to treat everything inside literally, preventing any expansion or special interpretation.

Other options include characters tied to redirection or quoting rules, which are not the primary signal for when to use single quotes to avoid expansion, and thus don’t align with the intent of avoiding shell expansion as directly.