What do I use to validate a file againt it's MD5 checksum?

[edesignuk]

OK, so I have a file, and I also have it's MD5 checksum, now I don't really know the first thing about what an MD5 checksum is, but I presume it's a way to validate if the file is complete/intact.
How do I check a file against it's MD5 checksum?

Thanks!

[caveman_uk]

Use

md5 <filename>

in the terminal. It will give the checksum of the file. You check the one it calculated against the one you've been given with the file.

[edesignuk]

<feels like an idiot> Thanks! So simple! </feels like an idiot>