- Simple command-line argument parsing that requires no external dependencies. Definitions are parsed from help info,
so there is no duplication
- Helpful magic variables like `__file`, `__dir`, and `__os`
- Logging that supports colors and is compatible with [Syslog Severity levels](http://en.wikipedia.org/wiki/Syslog#Severity_levels) as well as the [twelve-factor](http://12factor.net/) guidelines
Although this last option introduces a Node.js dependency, this does allow for easy version pinning and distribution in environments that already have this prerequisite. But this is optional and nothing prevents you from just using `curl` and keep your project or build system low on external dependencies.
As of `v1.0.3`, b3bp adds some nice re-usable libraries in `./src`. Later on we'll be using snippets inside this directory to build custom packages. In order to make the snippets in `./src` more useful, we recommend these guidelines.
### Library exports
It's nice to have a bash package that can be used in the terminal and also be invoked as a command line function. To achieve this the exporting of your functionality *should* follow this pattern:
```bash
if [ "${BASH_SOURCE[0]}" != ${0} ]; then
export -f my_script
else
my_script "${@}"
exit $?
fi
```
This allows a user to `source` your script or invoke as a script.
```bash
# Running as a script
$ ./my_script.sh some args --blah
# Sourcing the script
$ source my_script.sh
$ my_script some more args --blah
```
(taken from the [bpkg](https://raw.githubusercontent.com/bpkg/bpkg/master/README.md) project)
- Use `__double_underscore_prefixed_vars` to indicate global variables that are solely controlled inside your script, with the exception of arguments wich are already prefixed with `arg_`, and functions, over which b3bp poses no restrictions.
