Return the codename for the release of the current OS distribution,
as a string.
If the distribution does not have a codename, an empty string is returned.
Note that the returned codename is not always really a codename. For
example, openSUSE returns "x86_64". This function does not handle such
cases in any special way and just returns the string it finds, if any.
**Lookup hierarchy:**
the codename within the "VERSION" attribute of the os-release file, if
provided,
the value of the "Codename" attribute returned by the lsb_release
command,
the value of the "<codename>" field of the distro release file.
Return the codename for the release of the current OS distribution, as a string. If the distribution does not have a codename, an empty string is returned. Note that the returned codename is not always really a codename. For example, openSUSE returns "x86_64". This function does not handle such cases in any special way and just returns the string it finds, if any. **Lookup hierarchy:** the codename within the "VERSION" attribute of the os-release file, if provided, the value of the "Codename" attribute returned by the lsb_release command, the value of the "<codename>" field of the distro release file.