The Java TM Tutorial

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Trail: Essential Java Classes
Lesson: Setting Program Attributes

## POSIX Conventions for Command Line Arguments

> Command-Line Arguments warns that the use of command-line arguments in a Java program may cause that program to be unportable (that is, it will not be 100% Pure Java). If a program requires command-line arguments, then it should follow the POSIX conventions for them. The POSIX conventions are summarized here:
> - An option is a hyphen followed by a single alphanumeric character, like this: `-o`.
> - An option may require an argument (which must appear immediately after the option); for example, `-o argument` or `-oargument`.
> - Options that do not require arguments can be grouped after a hyphen, so, for example, `-lst` is equivalent to `-t -l -s`.
> - Options can appear in any order; thus `-lst` is equivalent to `-tls`.
> - Options can appear multiple times.
> - Options precede other nonoption arguments: `-lst nonoption`.
> - The `--` argument terminates options.
> - The `-` option is typically used to represent one of the standard input streams.

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