Did you try it to see how it worked? I suggest doing so.
Make the file "read only"?
Or does it change the File Type to something called a "Stationery Pad"?
It does neither of those.
First, did you try it? Second, does it solve the problem?
If it doesn't solve the problem, or even if it does, why does the mechanism matter?
If you want to see what it
doesn't do, open a "Get Info" window and notice that checking "Stationery pad" has no effect on the read/write permissions.
If at some point you need to change the Stationery pad document, simply uncheck the checkbox; edit, save, and close the file; then recheck the checkbox.
To me, an "alias" is this...
You create "File1.txt" and save it somewhere. Next, you create "Alias to File1.txt" and that is a "pointer" back to the file "File1.txt"
So when if you update "File1.txt", then when you open "Alias to File1.txt", it as if you are looking at "File1.txt".
And, I believe, if you instead open "Alias to File1.txt" and make changes, because the alias is a pointer back to the actual file, when you update the alias, you are really updating the original file, "File1.txt", right?
That's basically correct, except for one thing. In this sentence:
So when if you update "File1.txt", then when you open "Alias to File1.txt", it as if you are looking at "File1.txt".
there is no "as if". When you open an alias, you are opening the actual original file it points to.
An alias file contains no editable content. When you open an alias, the pointed-to file itself, i.e. the target, is actually being opened. This is why your earlier description is wrong. That description (and some of the above) makes it seem like there's two things being edited: an original file and its alias. But that's not possible with an alias file, because an alias file contains nothing editable. You can see this by making a simple yet systematic test (a document file and an alias to it) and carefully observing what gets opened when you open the alias file. The title bar of the window will show exactly what that is. I suggest that you do this experiment to get a hands-on sense of exactly how aliases files work. Observe carefully, and don't jump to conclusions.
But I already did that, and apparently it didn't actually work.
Exactly what did you do? List every step. Be specific.
When your "Save as" dialog appears, does it look like this?
If so, do you see the checkbox at the bottom "Keep changes in original document"?
(Note 1: If you see the checkbox, the wording may differ somewhat, because the above is from an older TextEdit version than yours.
Note 2: The checkbox will only appear if you've changed the original file contents in some way. If there are no changes made, then there are no changes to keep in the original, so the checkbox doesn't appear.)
If you see the checkbox in your dialog, is it checked or unchecked?
If it's checked, uncheck it, then complete the save. Now go back and see if the original document contains the changes or not.
Describe your results. Be specific.
The above image is taken from this article:
http://www.macobserver.com/tmo/article/os-x-mountain-lion-how-apple-rescued-save-as
You should also read this article:
http://tidbits.com/article/13187
It has the best explanation I've read of how the two System Preferences > General checkboxes work.
Have you ever done that?
Does it work?
I have both checkboxes checked under System Preferences > General. They work.
I also have unchecked the "Keep changes in original document" checkbox in TextEdit's "Save as" dialog. That checkbox is sticky, and it defaults to the last value used. So once unchecked, it will appear unchecked by default in all subsequent Save as dialogs in TextEdit. This also works.
I use TextEdit A LOT as a "scratch pad" - especially for code and queries, and I don't want OS-X saving things without me okaying it, even if I can supposedly roll things back.
(Try looking at an SQL query that is 30 lines long, and trying to figure out which "version" is the one you want?!)
I'm a programmer myself.
If TextEdit fails to meet your needs, even with "Keep changes in original document" unchecked, then I suggest switching to a programmer's text editor. There are plenty to choose from, and several are free. You will have to try them to find out exactly how they work, and whether that fits your work flow. Asking for advice can only go so far; at some point you have to try it and see what happens.
An example free editor is TextWrangler. You can look on the Mac App Store for others. Use search criteria such as:
programming editor
programmer editor
developer editor
I've heard of SymLinks but don't understand what purpose they serve...
They serve the same purpose as alias files.
(I looked at the link, but it didn't really make any sense to me?!)
Did you study the article, or did you just give it a quick glance?
The 2nd & 3rd paragraphs seem clear to me:
Symbolic links operate transparently for most operations: programs that read or write to files named by a symbolic link will behave as if operating directly on the target file. ...
A symbolic link contains a text string that is automatically interpreted and followed by the operating system as a path to another file or directory. This other file or directory is called the "target". The symbolic link is a second file that exists independently of its target. ...
The article even mentions Mac OS alias files, which have their own article.
