Bang Prefix

Bang prefixing to reverse default actions

Description

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

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

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This document was generated from gen/user-guide/bang-prefix_doc.yaml.