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.