'==' can not compare file handles. We can use fileno() function to
compare numerically file numbers. Code without this returns
"connection successful" when it timeouts and $fd is "undefined".

correcting "Can't use an undefined value as an ARRAY reference at /opt/resmon/lib/Core/ChefLastGoodRun.pm line 88." error

On some systems, there are lines in /proc/meminfo that don't match the regex.
Currently these cause resmon to throw an error and give a blank metric. This
change skips those metrics rather than throwing an error.

value to determine whether to use cache_command or run_command.

$commhist{$command}->$now which is distinctly not what it actually is.

report its output.

Credit: Michal Racek <michal.racek@t-systems.sk>

In Resmon 1, it was possible to add an interval parameter to an individual
check to give it a larger check interval than regular checks (cached results
would be returned in the meantime). This functionality wasn't properly carried
over into resmon 2, and this commit fixes that.

Allow setting an absent => X config param for file checks.  If set will return all the metrics the module normally would, but with their integer values set to whatever you defined for absent.  present will still = 0 and text values will be undef

Occasionally on some systems, the data returned from the shared state file is
bad/blank, despite locking. Ideally we'd find the cause of this and fix it,
but various attempts haven't identified exactly why this happens (including
running fsync after writing and before unlocking). If the data returned is
blank, we should use the latest available data rather than returning blank
data to the user/monitoring system.

This allows you to have multiple checks on the same file, but with a different
match string in order to count different types of errors.

Allow escaped commas in config parameters.  Update Core::SMART docs and stop prefixing metrics with the disk name, as Resmon already uses check_name in the final metric output.

Uses ps to count the amount of processes on a system. I've placed this
into the Linux area as I've only tested it on a Linux system (Ubuntu
11.04).

To avoid warning messages like:
"Use of uninitialized value $bits in string eq at /opt/resmon/lib/Resmon/Config.pm line 16..."
$bits variable should be checked if it is defined before comparison with empty string

Hosts allow-deny lists are the coma or blank separated lists of
a dotted decimal IPv4 addresses of the form a.b.c.d. to match incoming machine’s IP address exactly,
or an 'ipaddr/n' where ipaddr is the IP address and n is the number of one bits in the netmask.
The first to occur match gives the result, skipping other rules.
If nothing matches IP is allowed.