I downloaded data in Ubuntu which has an extension .text/plain bit when I copied it to my Windows 10 through USB the file extension is changed to '.file'. What should I do now to open it?
It seems that opening the file has worked on Ubuntu, because GNOME can "associate a media type with a file by examining both the filename suffix and the contents of the file" (Wikipedia).
To open the file in Windows, you can simply change the extension from
.txt, which is the most likely filetype. However, depending on where and for what purpose you downloaded the file, it could also be a
.dat (data) or other file. If you don't know how to change the file type, I'd advice to Google for it as that seems out of scope for this Ubuntu-oriented site :)
Are you 100% sure that the file extension is
.text/plain???? I'm 99% sure that it's not possible. Maybe you are talking about file content?
Can you show us the output of runing
To open it on Windows, it should be enough renaming its extension to something you know. Do you know what type of file it is? if you downloaded a plain text file, you can rename it to
your_filewith_strange_extension.txt. The output of running (on linux)
file your_filewith_strange_extension should give you a hint about the file contents if you don't know what it is