The following table lists all the Ruby’s Predefined Constants −
NOTE − TRUE, FALSE, and NIL are backward-compatible. It’s preferable to use true, false, and nil.
| Sr.No. | Constant Name & Description |
|---|---|
| 1 | TRUESynonym for true. |
| 2 | FALSESynonym for false. |
| 3 | NILSynonym for nil. |
| 4 | ARGFAn object providing access to virtual concatenation of files passed as command-line arguments or standard input if there are no command-line arguments. A synonym for $<. |
| 5 | ARGVAn array containing the command-line arguments passed to the program. A synonym for $*. |
| 6 | DATAAn input stream for reading the lines of code following the __END__ directive. Not defined if __END__ isn’t present in code. |
| 7 | ENVA hash-like object containing the program’s environment variables. ENV can be handled as a hash. |
| 8 | RUBY_PLATFORMA string indicating the platform of the Ruby interpreter. |
| 9 | RUBY_RELEASE_DATEA string indicating the release date of the Ruby interpreter |
| 10 | RUBY_VERSIONA string indicating the version of the Ruby interpreter. |
| 11 | STDERRStandard error output stream. Default value of $stderr. |
| 12 | STDINStandard input stream. Default value of $stdin. |
| 13 | STDOUTStandard output stream. Default value of $stdout. |
| 14 | TOPLEVEL_BINDINGA binding object at Ruby’s top level. |