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#290 in Command-line interface

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crates.io tests docs.rs

Command Line Options Parser

Simple command line parser in Rust.

cmdopts parses GNU-like command line options for long and short formats. Optional argument (aka option's value) may be associated with an option. The parsing routine parse_opts() accepts two user callbacks:

  • opt_i() provides parser with a context the parsed option may be used,
  • opt_h() is the actual handler of the option.

The library doesn't interpret parsed options, rather passes them to the user's handler to further processing. The idea is similar to getopt(3) and getopt_long(3) routines.

Options Format

Short format

All options starting with a single hyphen character - are short options. For example: -a -b -c constitute 3 short options. These options may grouped into a single block of options as -abc.

If a short option requires an argument, the argument may be provided directly after the option or separated by white-space(s): -dARG or -d ARG.

If short options are grouped into a block, the last one may be provided with an argument. For example: -abcdARG or -abcd ARG is equivalent to -a -b -c -d ARG, where -a -b -c don't have an argument, while -d does.

Long format

If an option starts with -- it's long format option. For example --help. Long options may not be formed into a group. An argument may be provided to the long-format option directly after = character or followed by white-space(s): --config=FILE or --config FILE.


See enclosed examples for details.


2 clause BSD license. See LICENSE file for details.

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