There is no traditional 'execute' command in Unix.
It is possible to use BSD software on Unix systems. It is possible but many do not and they use other softwares on Unix systems beside the BSD software.
Unix can be used on a large number of mainframes, servers, and workstations. If you would like to use a certified UNIX system on commodity hardware, Solaris 10 can be downloaded free of charge for non-commercial use.
Yes, quite a bit of companies and users use unix.
You should be able to download the Unix Services for Windows, version 3.5, from Microsoft (free). There are other shell emulators that are available for Windows, which would allow you to use Unix type shell scripting without installing any additional OS. Your question about "virtual UNIX" is unclear ..
Yes you can. Unix understands both FAT32 and NTFS file systems.
In Unix, use the 'man' command.
Use useradd command
Use the command 'passwd'
No, it is unix-based but Linux is a kernel not an operating system.Ubuntu,Linux Mint,Debian,and puppy Linux,ect. are OS's that use the Linux kernel.
The usual difficulty that people report concerning UNIX is the use of the command line. The command line has a lot of power and the commands may seem somewhat arcane at times. Like anything else, you have to study what the commands do and how to use them to harness the power of UNIX, but once you do that it isn't that difficult to use.
cat /proc/version The above answer will only work on certain systems. For most Unix systems, use the 'uname' command to get the Unix version. AIX uses the oslevel command.