I was running Cygwin in Windows XP Pro SP3 on my old machine, and I came across a feature in the Linux/Unix command-line text editor
nano where it would automatically generate backups to any text file I opened and edited in it. It did, all right ... it marked each backup file name with a tilde (~) at the very end of the name. I had already associated -- for all the work I put into it, let's say I "cudgeled" Windows into making the association -- the
.bak extension as "Backup file."
I asked on several Linux-related forums whether or not, short of customizing the source code and recompiling nano, there was a way to get it to change how it named the backups of files I edited in it. I got no answers that were worth anything: most were along the lines of "Here's how you get nano to make backups automatically, and here's what you do so you don't anymore." Why did I find replies like that worthless? Because I could get asmuch from the text under a Google "hit" link.
So my advice to all and sundry is: don't put too much stock in an exotic or "custom" file association, as you may run into an application or two that doesn't use it or, worse, is hostile towards it in the form you know. A prime example from my own past in Mac OS is the '.bin' extension -- which everywhere else relates to CDs or DVDs, but in Mac OS stands for a file encoded in MacBinary,
unless you're using NTI's DragonBurn.
BZT