The ypxfr command moves an NIS map in the default domain for the local host to the local host by making use of normal NIS services. It creates a temporary map in the directory /var/yp/ypdomain (this directory must already exist; ypdomain is the default domain for the local host), fills it by enumerating the map's entries, fetches the map parameters (master and order number), and loads them. It then deletes any old versions of the map and moves the temporary map to the real name.
If run interactively, ypxfr writes its output to the terminal. However, if it is started without a controlling terminal, and if the log file /var/yp/ypxfr.log exists, it appends all its output to that file. Since ypxfr is most often run from the privileged user's crontab file, or by ypserv, the log file can retain a record of what was attempted, and what the results were.
For consistency between servers, ypxfr should be run periodically for every map in the NIS data base. Different maps change at different rates: a map might not change for months at a time, for instance, and can therefore be checked only once a day. Some maps might change several times per day. In such a case, you might want to check hourly for updates. A crontab(1) entry can be used to automatically perform periodic updates. Rather than having a separate crontab entry for each map, you can group commands to update several maps in a shell script. Examples (mnemonically named) are in /usr/sbin/yp: ypxfr_1perday, ypxfr_2perday, and ypxfr_1perhour.
Refer to ypfiles(4) for an overview of the NIS name service.
Do not send a "Clear current map" request to the local ypserv process. Use this flag if ypserv is not running locally at the time you are running ypxfr. Otherwise, ypxfr complains that it cannot communicate with the local ypserv, and the transfer fails.
Force the transfer to occur even if the version at the master is not more recent than the local version.
This option is for use only by ypserv. When ypserv starts ypxfr, it specifies that ypxfr should call back a yppush process at the host server, registered as program number prog, and waiting for a response to transaction tid.
Specify a domain other than the default domain.
Get the map from host, regardless of the master. If host is not specified, ypxfr asks the NIS service for the name of the master, and tries to get the map from there. host must be a valid host name.
Specify a source domain from which to transfer a map that should be the same across domains.
Script to run one transfer per day, for use with cron(1M)
Script to run two transfer per day, for use with cron(1M)
Script for hourly transfers of volatile maps
Privileged user's crontab file
See attributes(5) for descriptions of the following attributes: