cannot run hplp -3.18.6.run file is corrupt

"… If you continue editing …" You should not edit that file, but executed it with a shell.

Execute the command

sh /home/ray/Downloads/hplip-3.18.6.run

and provide answers as appropriate.

see https://developers.hp.com/hp-linux-imaging-and-printing/install/install/index

Hi RayArdia,

To install HPLIP driver please follow the below steps:

1. Goto https://developers.hp.com/hp-linux-imaging-and-printing/gethplip and download and install the latest driver for your distro.
2. To install, run the command "sh hplip-3.18.6.run" in terminal from the location where you have downloaded the driver.

If not working, please share the printer and distro details.

Also run the command "sudo hp-logcapture" and share the logs.

Regards,
Srinivas Teja.

Thanks for your help, but I need a little more....
Got as far as this:-
'PRINTER SETUP
-------------
Please make sure your printer is connected and powered on at this time.
Do you want to setup printer in GUI mode? (u=GUI mode*, i=Interactive mode) : u

HP Linux Imaging and Printing System (ver. 3.18.6)
Printer/Fax Setup Utility ver. 9.0

Copyright (c) 2001-15 HP Development Company, LP
This software comes with ABSOLUTELY NO WARRANTY.
This is free software, and you are welcome to distribute it
under certain conditions. See COPYING file for more details.

Searching... (bus=net, timeout=5, ttl=4, search=(None) desc=0, method=slp)
error: No devices found on bus: net
warning: HPLIP cannot detect printers in your network. This may be due to existing firewall settings blocking the required ports.
                When you are in a trusted network environment, you may open the ports for network services like mdns and slp in the firewall. For detailed steps follow the link.
                 http://hplipopensource.com/node/375

Where do I go from here?

BTW you asked for results from "sudo hp-logcapture", here it is:-

ray@ray-Aspire-5735:~$ sudo hp-logcapture
[sudo] password for ray:
\Archiving system logs (i.e. syslog, message, error_log). Press (y=yes*, n=no, q=quit):y
Existing /var/log/syslog log file copied to /var/log/syslog.8.gz
Existing /var/log/cups/error_log log file copied to /var/log/cups/error_log.8.gz

Please perform the tasks (Print, scan, fax) for which you need to collect the logs.
Are you done with tasks?. Press (y=yes*, q=quit):q
warning: User exit

Hi RayArdia,

Looks like you are trying to add printer through network, see if your system and printer are in the same network.
then do hp-setup <printer ip> to add printer.
You can also connect your printer with usb if usb support is present for your printer.

To help furthur, please share the printer and distro details.
Also " sudo hp-logcapture" command will generate logs, Please attach all of them here.

Regards,
Srinivas Teja.

Printer is HP Officejet 3831 connected via same wireless network as all computers/tablets/phones etc. Distro Ubuntu 16.04.
Printer seems to be working OK now But just to be sure I did:-
ray@ray-Aspire-5735:~$ hp-setup hp:/net/OfficeJet_3830_series?zc=HP48BA4E7B091D

HP Linux Imaging and Printing System (ver. 3.18.6)
Printer/Fax Setup Utility ver. 9.0

Copyright (c) 2001-15 HP Development Company, LP
This software comes with ABSOLUTELY NO WARRANTY.
This is free software, and you are welcome to distribute it
under certain conditions. See COPYING file for more details.

Searching for device...
error: Device not found. Please make sure your printer is properly connected and powered-on.
^C
ray@ray-Aspire-5735:~$
Note, printer was powered on and enabled at this point, I checked.

A bit puzzled still!
Also noted that on a couple of occasions when I tried, and failed, to print I found that printer was not showing 'Enabled', changed to Enabled again and all was well

What is the ip address of the printer?

For network devices the address should be something like
hp:/net/OfficeJet_3830_series?ip=192.168.1.1