change variable

The value of variable has changed. The change event is roughly equivalent to:

when step { if [ $last_value !=$[variable]] 
            then
                 stop
            else
                 last_value=$[variable]
            fi
          }

This event is implemented using single-stepping. For faster performance, use the access event (see access mode address-expression [, byte-size-expression]).

The first time variable is checked causes one event, even though no change is detected. This first event provides access to the initial value of variable. Subsequent detected changes in the value of variable trigger additional events.