Understanding uname output

Question

What do the different fragments of uname -a mean? The following is an example output:

 Linux mymachine 2.6.18-194.e15PAE #1 SMP Fri Apr 2 15:37:44 EDT 2010 i686 i686 i386 GNU/Linux 

I understand that Linux is the OS, 2.6.18-194.e15PAE is the kernel version. What do the rest of the pieces mean?

Appreciate your help.

Answer 1

In order of the field:

• "Linux": the name of the kernel of the machine (for example, the OS).
• "mymachine": host name of the node (for example, hostname).
• "2.6.18-194.e15PAE": kernel version
• "# 1 SMP Fri Apr 2 15:37:44 EDT 2010": kernel version and build time.
• "i686 i686": processor type and hardware platform.
• "i386": processor architecture. (These and the two above basically mean the same thing on most systems. They usually differ only on some embedded platforms.)
• "GNU / Linux": name of the operating system.

For comparison, uname -a from my Mac reads:

• Darwin (hardware name)
• "my car"
• "Darwin kernel version 11.0.0" (version)
• "Sat Jun 18 12:56:35 PDT 2011; root: xnu-1699.22.73 ~ 1 / RELEASE_X86_64" (build time)
• "x86_64" (processor architecture)
• (For any reason, the name of the operating system is excluded by uname OS X, as well as several other fields.)