5 ms·

Introduction to FreeBSD for Linux Users

72 points by pselbert 12y ago

sophacles 12y ago
I'd really like to see one of these get written one day from a couple of deeper perspectives... The difference between Linux and FreeBSD is bigger than just "they are variants on a theme", even if this is true at the sysadmin level, and even from the application programming point of view. At a deeper level - things like "non-posix" syscalls vary a lot, and the subsystems they interact with are wildly different. Some of it is again variations on a theme - a special syscall vs an ioctl, or what not, but the way those subsystems interact starts becoming very interesting at a systems architecture level. For instance, I might want to write a specialized networking tool mostly in userland in linux, via nf_queue, whereas in FreeBSD I might want to split the operations between the kernel (via netgraph) and userland (via the pf equivalent to nf_queue). It would be nice to see a nice write-up, or survey of writeups of the differences at that level.
- beigeotter 12y ago
  We accept (and pay for) article submissions. If you may be interested in potentially writing this piece, you can check out our program: https://www.digitalocean.com/community/get-paid-to-write https://www.digitalocean.com/community/get-paid-to-write
  - sophacles 12y ago
    Oh cool - that's a neat program you folks have going! This might be a good excuse to dig into this for myself, rather than hoping someone else does it for me :)
    - beigeotter 12y ago
      Sounds awesome!
hetman 12y ago
I would be interested to know the reasoning behind using different shells for interactive sessions vs. scripting on FreeBSD. Wouldn't it be easier to pick one for both? Is this just historical legacy?
- sophacles 12y ago
  Many linux distros do this too... e.g. debian based systems default to bash or zsh for interactive shells, and use dash for /bin/sh (aka scripting).
  - deleted 12y ago
    [deleted]
  - aruggirello 12y ago
    Ubuntu does it too. That's the reason debian and Ubuntu weren't hit too hard by the Bash bug.
  - hetman 12y ago
    True but dash and bash are mostly interchangeable. I should have clarified that what was strange to me was the choice of shells with incompatible syntax.
- smhenderson 12y ago
  I'm not sure why FreeBSD defaults to csh for interactive use other than it's probably just developer preference on their part. But for scripting, this old gem kept coming up for me when reading about FreeBSD: http://www.perl.com/doc/FMTEYEWTK/versus/csh.whynot http://www.perl.com/doc/FMTEYEWTK/versus/csh.whynot It's basically a bunch of reasons why c shell scripting is not recommended...
- talideon 12y ago
  You can blame Bill Joy for that. Allegedly, it was him who made csh the default root shell way back in the day. The reason it was never changed to sh or ksh subsequently is simply that it was never that big a deal: tcsh is a solid interactive shell, it sucks for scripting.
lucb1e 12y ago
What I like about this article is that it seems very unbiased. Most articles highlight a lot of key features from (GNU/)Linux or FreeBSD, depending on whom they're written by. This reads like a basic overview of how the systems came to be and why they work the way they work.

72 points by pselbert 12y ago

I'd really like to see one of these get written one day from a couple of deeper perspectives... The difference between Linux and FreeBSD is bigger than just "they are variants on a theme", even if this is true at the sysadmin level, and even from the application programming point of view. At a deeper level - things like "non-posix" syscalls vary a lot, and the subsystems they interact with are wildly different. Some of it is again variations on a theme - a special syscall vs an ioctl, or what not, but the way those subsystems interact starts becoming very interesting at a systems architecture level. For instance, I might want to write a specialized networking tool mostly in userland in linux, via nf_queue, whereas in FreeBSD I might want to split the operations between the kernel (via netgraph) and userland (via the pf equivalent to nf_queue). It would be nice to see a nice write-up, or survey of writeups of the differences at that level.

beigeotter 12y ago
We accept (and pay for) article submissions. If you may be interested in potentially writing this piece, you can check out our program: https://www.digitalocean.com/community/get-paid-to-write https://www.digitalocean.com/community/get-paid-to-write
- sophacles 12y ago
  Oh cool - that's a neat program you folks have going! This might be a good excuse to dig into this for myself, rather than hoping someone else does it for me :)
  - beigeotter 12y ago
    Sounds awesome!

hetman 12y ago

I would be interested to know the reasoning behind using different shells for interactive sessions vs. scripting on FreeBSD. Wouldn't it be easier to pick one for both? Is this just historical legacy?

sophacles 12y ago
Many linux distros do this too... e.g. debian based systems default to bash or zsh for interactive shells, and use dash for /bin/sh (aka scripting).
- deleted 12y ago
  [deleted]
- aruggirello 12y ago
  Ubuntu does it too. That's the reason debian and Ubuntu weren't hit too hard by the Bash bug.
- hetman 12y ago
  True but dash and bash are mostly interchangeable. I should have clarified that what was strange to me was the choice of shells with incompatible syntax.
smhenderson 12y ago
I'm not sure why FreeBSD defaults to csh for interactive use other than it's probably just developer preference on their part. But for scripting, this old gem kept coming up for me when reading about FreeBSD: http://www.perl.com/doc/FMTEYEWTK/versus/csh.whynot http://www.perl.com/doc/FMTEYEWTK/versus/csh.whynot It's basically a bunch of reasons why c shell scripting is not recommended...
talideon 12y ago
You can blame Bill Joy for that. Allegedly, it was him who made csh the default root shell way back in the day. The reason it was never changed to sh or ksh subsequently is simply that it was never that big a deal: tcsh is a solid interactive shell, it sucks for scripting.

lucb1e 12y ago

What I like about this article is that it seems very unbiased. Most articles highlight a lot of key features from (GNU/)Linux or FreeBSD, depending on whom they're written by. This reads like a basic overview of how the systems came to be and why they work the way they work.