How to determine encoding table of a text file

I have .txt and .java files and I don't know how to determine the encoding table of the files (Unicode, UTF-8, ISO-8525, …). Does there exist any program to determine the file encoding or to see the encoding?

Solution 1:

If you're on Linux, try file -i filename.txt.

$ file -i vol34.tex 
vol34.tex: text/x-tex; charset=us-ascii

For reference, here is my environment:

$ which file
/usr/bin/file
$ file --version
file-5.09
magic file from /etc/magic:/usr/share/misc/magic

Some file versions (e.g. file-5.04 on OS X/macOS) have slightly different command-line switches:

$ file -I vol34.tex 
vol34.tex: text/x-tex; charset=us-ascii
$ file --mime vol34.tex
vol34.tex: text/x-tex; charset=us-ascii

Also, have a look here.

Solution 2:

Open the file with Notepad++ and will see on the right down corner the encoding table name. And in the menu encoding you can change the encoding table and save the file.