Shaking hands is appropriate in many situations, particularly between men, but context and gender norms should be considered.
Common practice
In business or formal settings, men commonly greet each other with a handshake. Among women, handshakes are also common in professional environments.
Gender considerations
Between men and women, physical greetings are less predictable and depend on personal and cultural preferences. Waiting for the other person to initiate a handshake is usually the safest approach.
Alternative greetings
A verbal greeting or slight nod is always acceptable if unsure.