Linux Memory Check

I have used many memory checking programs for linux but wasn't really happy with them so I've written my own. This uses the /proc/meminfo file instead of the `free` command.
Currently it tracks: total, free, active, inactive, buffer and cache
It adds performance data for each of these.
I've written it to run small and clean. it seems to use about 1/2 the resources than the other checkers I've found.
There are a number of things I can add however the current version suits my needs. Perhaps if I find the time or enough people bug me about it I will put in some additional features.
version 1.0.1 to change the order you see the information along with fixing the performance data
version 1.1.0 adds the -f option which counts the 'cached' memory as part of 'free'
version 1.1.1 fix view of cached memory
version 1.2.0 fixed a bug in the input check for critical and warning, updated error messages to be more detailed.