> compare the BSD utils to the GNU utils and the style difference is very visible.

Well, what style difference exactly? GNU utils tend to be more verbose. Other than that, what is the difference in style?

I do not know which is the difference, but you really feel a difference.

It might be of homogeneity, i.e. the FreeBSD tools behave in a consistent way, while there are significant differences between the Linux tools, depending on which were the opinions of their particular authors about how the traditional UNIX tools should be changed.

For instance, at some point in time, long ago, in Linux the traditional "ifconfig" and a few related commands have been replaced by "ip", for managing networking.

The Linux "ifconfig" needed an upgrade, as it could do only a small fraction of what the FreeBSD "ifconfig" could do. Nevertheless, until today, decades later, I have been unable to stop hating the Linux "ip".

I cannot say why, because in other cases when some command-line or GUI utility that I had used for many years was replaced by an alternative I instantly recognized that the new UI was better and I never wanted to use the old UI again.

So while both FreeBSD and Linux have started with the same traditional UNIX utilities, they have evolved divergently and now they frequently feel quite differently, in the sense that the various options in commands or in configuration files may match your expectations only when taking into account the identity of the OS. Overall FreeBSD has been more conservative, but there are also cases when it has made bigger changes, but such changes seem more carefully planned and less haphazard than in the Linux world.