what is the best way to determine system OS?

[Roel Schroeven]

Mike Meyer wrote:
>>In that case, it seems to be a better idea to check the version of
>>vmstat that's on the system. At least, I presume that such differences
>>in behaviour can be deduced from the vmstat version string.
> 
> 
> Hmm. That doesn't seem to work here:
> 
> guru% vmstat --version
> vmstat: illegal option -- -
> usage: vmstat [-aimsz] [-c count] [-M core [-N system]] [-w wait]
>               [-n devs] [disks]

The version on Debian Woody uses -V:

$ vmstat -V
procps version 2.0.7

Apparently it is quite a different program than yours; the -V option is 
cleary labeled in the man page, and it supports much less options:

$ vmstat --help
usage: vmstat [-V] [-n] [delay [count]]
               -V prints version.
               -n causes the headers not to be reprinted regularly.
               delay is the delay between updates in seconds.
               count is the number of updates.



-- 
If I have been able to see further, it was only because I stood
on the shoulders of giants.  -- Isaac Newton

Roel Schroeven