=head1 NAME

rrdinfo - extract header information from an RRD

=head1 SYNOPSIS

B<rrdtool> B<info> I<filename>
S<[B<--daemon> I<address>]>

=head1 DESCRIPTION

The B<info> function prints the header information from an RRD in
a parsing friendly format.

Check L<rrdcreate> if you are uncertain about the meaning of the
individual keys.

=over 8

=item I<filename>

The name of the B<RRD> you want to examine.

=item B<--daemon> I<address>

Address of the L<rrdcached> daemon. If specified, a C<flush> command is sent
to the server before reading the RRD files. This allows B<rrdtool> to return
fresh data even if the daemon is configured to cache values for a long time.
For a list of accepted formats, see the B<-l> option in the L<rrdcached> manual.

 rrdtool info --daemon unix:/var/run/rrdcached.sock /var/lib/rrd/foo.rrd

=back

=head1 EXAMPLE

This is the output generated by running B<info> on a simple RRD which
contains two data sources and one RRA. Note that the number after the
I<last_update> keyword is in seconds since 1970. The string B<NaN>
stands for I<*UNKNOWN*> data. In the example it means that this RRD
has neither minimum nor maximum values defined for either of its
data sources.

 filename = "random.rrd"
 rrd_version = "0001"
 step = 300
 last_update = 955892996
 header_size = 2872
 ds[a].type = "GAUGE"
 ds[a].minimal_heartbeat = 600
 ds[a].min = NaN
 ds[a].max = NaN
 ds[a].last_ds = "UNKN"
 ds[a].value = 2.1824421548e+04
 ds[a].unknown_sec = 0
 ds[b].type = "GAUGE"
 ds[b].minimal_heartbeat = 600
 ds[b].min = NaN
 ds[b].max = NaN
 ds[b].last_ds = "UNKN"
 ds[b].value = 3.9620838224e+03
 ds[b].unknown_sec = 0
 rra[0].cf = "AVERAGE"
 rra[0].pdp_per_row = 1
 rra[0].cdp_prep[0].value = nan
 rra[0].cdp_prep[0].unknown_datapoints = 0
 rra[0].cdp_prep[1].value = nan
 rra[0].cdp_prep[1].unknown_datapoints = 0

=head1 ENVIRONMENT VARIABLES

The following environment variables may be used to change the behavior of
C<rrdtoolE<nbsp>info>:

=over 4

=item B<RRDCACHED_ADDRESS>

If this environment variable is set it will have the same effect as specifying
the C<--daemon> option on the command line. If both are present, the command
line argument takes precedence.

=back

=head1 AUTHOR

Tobias Oetiker E<lt>tobi@oetiker.chE<gt>

