There are more similarities than differences between FreeBSD and Linux. Both are excellent operating systems, and both can serve the needs of most users quite well. Although there is more software available for Linux than for FreeBSD, FreeBSD can run almost all Linux software that is available, so this is not really an issue. When running Linux software under FreeBSD, performance is not really an issue, either, because FreeBSD actually runs some Linux software faster than Linux itself does.
Here are some of the most important differences between FreeBSD and Linux:
There is only one distribution of FreeBSD, whereas there are more than 30 distributions of Linux FreeBSD will work the same way on all systems in which it is installed. This is not true with Linux. Each Linux distribution has a slightly different way of doing things. For example, Slackware Linux uses BSD-type run control scripts. Debian Linux uses Sys V run control scripts. And Redhat Linux uses Sys V run control scripts, but stores them in a different location than standard Sys V UNIX does. This can be confusing for users who move from one distribution of Linux to another, because things may not work the same way in the other distribution.
FreeBSD is a complete operating system maintained by a core team; Linux is a kernel maintained by Linus Torvalds Linux is not a complete operating system. It is a kernel. As mentioned in the section on Windows, the kernel is the core of the operating system. It controls virtually all aspects of the operating system. The various companies that sell Linux distributions take the Linux kernel and package it with a bunch of other programs designed to work with Linux. Because each company has its own idea about what should be included in a distribution, you may find that a program you had available on one Linux system does not exist on another Linux system (although you could download and install it). This fact can also cause dependency problems when upgrading Linux. For example, you may upgrade your Linux kernel, only to find out that you need to upgrade several other packages as well. Because FreeBSD is a complete operating system, upgrades are generally easier to do because any dependencies are upgraded at the same time.
Anyone can contribute code to Linux; contributions to FreeBSD must be reviewed and accepted by the core team Although anyone can contribute to the FreeBSD project, it is much more of a coordinated effort than Linux is. Contributions to the FreeBSD source code need to be approved by the core team before they will be merged into FreeBSD. This is good for most users because you can be sure that the code has been checked for problems by people who know what they are doing. It also helps to ensure that the code will not cause problems with other code that already exists. (This is sometimes a common problem with Linux, which is why many Linux distributions seem to come with at least some part "broken" out of the box. Because there is only one FreeBSD base of FreeBSD code (commonly known as a "source tree"), this is far less of a problem with FreeBSD).
These are some of the most important differences between Linux and FreeBSD. Because FreeBSD has a single source tree that is controlled by a core team, it tends to be more stable than Linux, and therefore is often more suitable for a production environment. The main drawback to this is that new features are not always implemented as quickly in FreeBSD as in Linux. There is a trade-off here. Do you want stability for a production environment? Or, do you want the latest gizmos and gadgets to play with at the expense of performance and stability? 总得来说：FreeBSD相关严格一些，任何人可以修改linux的代码，但freebsd不是，它的修改要经过小组确认。 而且freebsd可以使用linux上的软件，且效率更高。 linux有30多个发行的版本，版本之一差异很大，而freebsd则各个版本保持连续性。