10.2.5 fail

If a test fails, it is usually because one of the docommand calls fails, and so direct calls to the fail function are rare. However, if you do want to call this function directly, you should supply as its argument a short description of what has gone wrong. For example, the docommand function uses fail in the following way:-

fail "$label: $1: Expected return value $2, got return value $rv"