What are the symbols for boolean AND, OR, NOT in Bash and what is notable about their behavior?

• A. AND = &&, OR = ||, NOT = !; In the shell, && runs the second command only if the first one succeeds, and || runs the second command only if the first one fails.
• B. AND = and, OR = or, NOT = not; They always evaluate strictly left-to-right.
• C. AND = &, OR = |, NOT = ~; They have no special semantics.
• D. AND = +, OR = -, NOT = !; They are used to perform arithmetic.

Answer: (A)

In Bash, the boolean-like control operators are &&, ||, and !. They aren’t just true/false operators; they act on the exit status of commands. A command that finishes with exit status 0 is considered success (true), while a non-zero exit status is failure (false). Using this, && runs the second command only if the first one succeeds, enabling short-circuiting. Using || runs the second command only if the first one fails, also short-circuiting. The NOT operator negates the exit status of the following command, so it flips success to failure and vice versa, which is handy in conditionals. Other symbols like words such as and/or/not, or symbols like & (background), | (pipe), or arithmetic operators don’t represent the same boolean control behavior in this context.