UNIX V/s Linux

Sun's Solaris, HP's HP-UX and IBM's AIX are the most popular UNIX flavors available today. They are licensed versions of UNIX and are having a significant amount of cost. Technical support is also available. On the other hand Linux is a free software alternative to the commercial flavors of UNIX and are available without any cost. But do not have a standard technical support mechanism.

Commercial versions are standard considering the requirement, development, testing and support. So each release is consistent. But Linux is very inconsistent compared to UNIX.

UNIX flavors are targeted to particular hardware architecture. But Linux is supposed to be compatible as possible.

Source code of Linux kernel is available. UNIX flavors are available as binary only. They are not modular as Linux.

File system support is limited in UNIX. But Linux supports almost all file systems.

Core applications present in UNIX and Linux are similar. Most of the open source applications are available in Linux. And these are ported to UNIX as well. But enterprise-level applications and closed-source applications will not be present in Linux but can be in UNIX.