What's the proper plural for file extensions?

Question

I have one .msi. Then I get another. Do I now have:

two .msis

or

two .msi's

or

two '.msi's

or something else?

You could bypass this altogether and just say "two .msi files". Unless, of course, you have a word/character/space limit. — Pam, Jul 26 '19 at 13:47
Are you asking about grammar or orthography? Grammar is what you say aloud and hear; orthography is what you write. — tchrist, Jul 26 '19 at 13:55
@tchrist I disagree with the close vote. They're similar but clearly not identical - a file extension is not necessarily an acronym. txt is short for 'text'. I can even create my own extensions however I want. — Sarov, Jul 26 '19 at 19:36
I'm interested in the conventions are for this, and agree with @Sarov that this question is distinct from the 'duplicate' – I still don't have an answer for this question from reading the other — Unrelated, May 04 '21 at 00:48
One approach could be to capitalize the extension: e.g. two .CSVs – though it's much less common these days to see capitalized extensions in the wild — Unrelated, May 04 '21 at 00:49

score 5 · Answer 1 · answered Jul 26 '19 at 13:47

One easy way round it is to write

two .msi files

which also makes it clear to anyone who doesn't know what .msi means.

Another solution is to use uppercase letters for the file extension:

two MSIs
two .MSIs

1 Answers1