Long flags are a GNUism, not a "standard" by any means. The closest that comes to a standard in this space are POSIX utility conventions [1]. [1]: https://pubs

Long flags are a GNUism, not a "standard" by any means. The closest that comes to a standard in this space are POSIX utility conventions [1]. [1]: https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap12.html https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1...