Near

Where do I find detailed instructions on using the "near" component of hal. I see it used in examples but unable to find how to use it.

Have you read the (rather terse) manual page?

man near

Terse is the word, isn't it?
linuxcnc.org/docs/2.7/html/man/man9/near.9.html

You need to load the component then add it to a thread so that it gets updated every servo cycle Then connect the inputs and outputs and set the tolerance and comparison value
The comparison value can be supplied by another HAL pin if required.

Thanks for that info. That does work however it is more convenient in my situation to be able to access it on line. Is that possible. My linux machine is on the bridgeport in my shop, while I'm sitting here in my kitchen on my laptop.
Is there a way of getting to this information online?

Docs (current branch): linuxcnc.org/docs/2.7/html/

Scroll down for the man pages

Example: linuxcnc.org/docs/2.7/html/man/man9/near.9.html

On a machine with LinuxCNC installed, you can always use the command line:

If you are lazy and forgetful like me you can also goggle:

man linuxcnc near

Yes, that finds it, however

linuxcnc haui near

doesn't find it for me.
It seems like you need man in the search data.

Now I have bookmarked
linuxcnc.org/docs/2.7/html/

You don't need "man" in the google search "linuxcnc near" or 'linuxcnc near.9" are enough to bring up the man page as the first couple hits. (At least for me, but maybe Google knows me too well.)