Is true (IS [NOT] TRUE) operator

The is true (IS TRUE) and is not true (IS NOT TRUE) are used to verify that a Boolean operand is true (or not). Note that empty IS TRUE will return false and empty IS NOT TRUE will return true.

For example:

findit -w 'content.contains("test") IS NOT TRUE'

Will show all the files that have not test in their content and all the files which their content is unreadable (for example, directories).