Who are these BSD Unix contributors

This is mostly a historic matter, for a number of reasons:

• Over the years, the System V based Unices have gotten a lot of BSD in them, and the BSDs have — to a lesser extent — adopted some System V features.

• A lot of the differences simply don't matter any more, like XTI/TLI, having been beaten out in the market of ideas by BSD sockets.

• The Unix market is consolidating. There are fewer weird nonstandard differences to deal with these days, and better tools for dealing with the ones that remain. One big area of difference is in how dynamic linkage works, for instance, but we have GNU libtool to deal with it now.

The best single resource I know of for learning about these sorts of differences is Advanced Programming in the Unix Environment by Stevens and Rago. If you have a special interest in networking and IPC, add in Stevens' Unix Network Programming, volume 1 and volume 2.

If you already have an earlier edition of APUE, it's still useful. The main thing the second edition added was explicit coverage of Linux and OS X, but since these are based on Unix, you could still puzzle out how to apply the information. The third edition updates this classic again for recent OS versions and adds some new material.

It is very tempting to want to define the differences between BSD and Linux. Just like Gilles said in the comments, it is not an easy task since they're so numerous and disparate. Very often, the differences won't even be noticeable at the user's level; everything has been worked out so that the OS behaves as you would expect a Unix to.

Moreover multiple distributions are available for each. No matter what you say about Linux/BSD generally, you'll often find a distribution that contradicts it.

The following is a list of comparisons I found scattered over the web.

• Here on U&L, a user has defined the following differences:

Big differences are (in my opinion of course):

• Userland (Linux uses GNU while BSD uses BSD)
• Integration (Linux is a collection of different efforts, BSD is much more unified at the core)
• Packaging (Linux typically manages installed software in binary packages - BSD typically manages a "ports" tree that you use to build software from sources)

Notice the word typically in his last point. Some Linux distributions will manage source code and conversely some BSDs will manage binary packages.

• Matthew D. Fuller has a lengthy comparison between BSDs and Linux you may want to look into. The article will compare both on Design level, Technical differences, Philosophies and finally address common Myths. Here are some excerpts:

BSD is what you get when a bunch of Unix hackers sit down to try to port a Unix system to the PC. Linux is what you get when a bunch of PC hackers sit down and try to write a Unix system for the PC.

--

BSD is designed. Linux is grown. Perhaps that's the only succinct way to describe it, and possibly the most correct.

• User vivek on FreeBSD forums writes:

Key differences:

1. FreeBSD full os. Linux is kernel. Linux distribution is os (100+ majro disrtos).
2. FreeBSD everything comes from a single source. Linux is like mix of lot of stuff.
3. BSD License vs GPL
4. FreeBSD Installer
5. BSD commands (ls file -l will not work) vs GPL command (ls file -l will work)
6. FreeBSD better and updated man pages.
7. BSD rc.d style booting vs Linux SysV style init.d booting

Here are some articles describing the history of each:

• Written by Dave Tyson, this article describes the history of many Unix variants (including of course BSD and Linux).

• Scott Barman describes how both operating systems came to be and how it forged his opinion:

I will give one "solid" opinion: If I had to choose one system that would act as my router, DNS, ftp server, e-mail gateway, firewall, web server, proxy server, etc., that system would run a BSD-based operating system. If I had to choose one system that would act as my desktop workstation, run X, all the application I like, etc., that system would run Linux. HOWEVER, I would have no problem running Linux as my work horse server or running the BSD-based system on my desktop.

Further reading

• This question here on U&L, compares existing BSDs, highlighting what they have in common.