16. Conditions

This section describes commands that are primarily useful for their exit status, rather than their output. Thus, they are often used as the condition of shell if statements, or as the last command in a pipeline.

16.1 false: Do nothing, unsuccessfully		Do nothing, unsuccessfully.
16.2 true: Do nothing, successfully		Do nothing, successfully.
16.3 test: Check file types and compare values		Check file types and compare values.
16.4 expr: Evaluate expressions		Evaluate expressions.