[derefr]

> why couldn't GNU/RedHat have just [modified] ifconfig rather than [having] ifconfig, ifup, ip, etc.

This comes down to one of the key differences between Linux and BSD: BSD "owns" its userland—the people who develop the kernel, or some system utility, can literally decide to change something, and then do a global search-and-replace on all usages of that something across all consuming projects. Because all those projects are "part of" BSD in a very literal sense. You can decide that ifconfig(8) should work differently, and bam, there you go, now it works differently. Now the tools that call it and parse its output work differently, too. Everything works differently; but everything still works. Document the new behavior in the man(1) pages.

Linux, meanwhile, is in essence a giant Mexican standoff: nobody can change the interface of the thing they're responsible for, without potentially breaking something someone else is doing that they're not aware of at all. So Linux devs, rather than changing old interfaces for the better, just leave the old interfaces where they are in a sort of "legacy-compat" mode, and build entirely new interfaces that work the way they "should." (And then people start to depend on the details of the new interface, and it all happens again five years later.)

[junk_disposal]

>This comes down to one of the key differences between Linux and BSD: BSD "owns" its userland—the people who develop the kernel, or some system utility, can literally decide to change something, and then do a global search-and-replace on all usages of that something across all consuming projects. Because all those projects are "part of" BSD in a very literal sense. You can decide that ifconfig(8) should work differently, and bam, there you go, now it works differently. Now the tools that call it and parse its output work differently, too. Everything works differently; but everything still works. Document the new behavior in the man(1) pages.

1. Linux doesn't care about ifconfig et. al. It's Debian/RedHat/Arch/Gentoo/Slackware that does. And they can do the same grep across their codebase.

They don't now for the same reason BSD doesn't just run in and change things, because lots of admins have scripts which aren't maintained by BSD which depend on existing config.

2. I would assume that the BSD ifconfig came first, so why didn't existing distros copy their system? Is it a BSD vs. SysV thing?