When I have a random file of unknown format with a file extension I've never heard of, where can I turn to find out about the extension. The obvious choice is to google the extension along with some combination of the words "file", "extension", and so on, but that just yields pages of spam websites peddling anti-virus ("Fix virus problems related to XYZ files!"). Is there any better way?
How to find out about an unknown file extension
file extension
Related Solutions
There is no requirement for a Markdown file extension, as other answers have explained. But in order for editors or parsers to guarantee that the file they are using is Markdown-formatted, they would look for one of the following extensions:
.markdown
.mdown
.mkdn
.md
.mkd
.mdwn
.mdtxt
.mdtext
.text
.Rmd
There are websites such as GitHub that only use a selection of these extensions for converting to HTML so developers will conform to their standard. (see examples below)
Personally, I have seen .markdown and .mdown used the most, and as a Linux user I would avoid using .md as this can also be a machine description file for compiling code with GCC.
Examples of extension usage:
GitHub: markdown, mdown, mkdn, mkd, md (source)
Elements Markdown Editor: markdown, mdown, mdwn, md
Vim markdown: markdown, mdown, mkdn, mdwn, mkd, md
Bitbucket: markdown, mdown, mkdn, mkd, md, text (source)
R Studio: Rmd
Further Reading
There is a Markdown mailing list that has interesting discussions about this topic: 1, 2.
And especially revealing is one of the explanations:
Markdown isn't meant to take over the format of a file, it's a way to subtly add information to the plaintext. Really, the presence of Markdown is metadata, not a file format.
...
No one opening a text file will be confused if they find Markdown syntax, it's pure bonus.In this sense, it makes sense to use ".text", ".txt", or whatever other plaintext extension is relevant.
...
An editor which knows nothing about Markdown won't care about the metadata and won't be confused by the variety of "non-standard" extensions, but will display and edit the plaintext just fine.
You can use the TrID tool which has a growing library of file type definitions for identifying files with.
Wildcards are supported, so in your example you could just put all the images to be examined in a folder, e.g. C:\verifyimages - then you can use the command:
trid C:\verifyimages\*
This will examine all files in the verifyimages folder.
There is also a GUI version available, TrIDNet:
There is documentation available on how you can you can easily integrate TrID or TrIDNet into Windows Explorer and Total Commander:
Windows Explorer
Total Commander
Best Answer
FILExt - The File Extension Source