The command does not persist through a reboot, at least on my machine.
There are multiple ways to make a command run at startup. For example: Create this text file:
Save the file with a name like ShareLPD.command (with a .command extension, NOT a .txt or other extension); put it in in a convenient folder. Go to System Preferences, Users & Groups, Login Items, and add the new file to the login items.#!/bin/bash
/usr/sbin/cupsctl 'BrowseLocalProtocols="cups dnssd lpd"'
exit
Alternatively, in the AppleScript editor, enter the following:
Save it as an Application in some convenient folder, and add that to the list of Login Items.do shell script "/usr/sbin/cupsctl 'BrowseLocalProtocols=\"cups dnssd lpd\"'"
There are probably plenty of other ways to do this.
In my own application (which runs WordPerfect for the Mac), I use an Applescript that launches a SheepShaver .sheepvm that is stored inside the AppleScript bundle itself. I've added a "do shell script" command that runs this command when my Applescript starts up, so I don't need to add anything to the Login Items.