Bang Prefix

Bang prefixing to reverse default actions

Some builtins support a bang prefix, !, which provides a shorthand negative action to default behavior. For example, set defines a variable where as !set will undefine a variable.

Sometimes the shortcut will be logical, like a not operator, as is the case with and where typically each result has to equal true normally or false if used in !and.

Sometimes the shortcut will be more philosophical, such as with config where normal operations is to query or set configuration but !config resets the configuration to defaults (thus operating the same as config default).

Please read the respecting commands doc for details on whether it supports a bang prefix and what the behavior of that prefix is.

See Also

• Pipeline: Overview of what a "pipeline" is
• Reserved Variables: Special variables reserved by Murex
• ! (not): Reads the STDIN and exit number from previous process and not's it's condition
• and: Returns true or false depending on whether multiple conditions are met
• config: Query or define Murex runtime settings
• or: Returns true or false depending on whether one code-block out of multiple ones supplied is successful or unsuccessful.
• set: Define a local variable and set it's value