Question

What is head revision and specific version in SVN?

Answer 1

The HEAD revision refers to the most current revision in a repository. If you are browsing the HEAD revision of your repository and one of your teammates commits a change, those new changes will be included when you decide to check out a working copy of that revisionor fetch specific information about it.
I want to checkout a specific revision of a folder in Subversion using the command line.
I don't see an option for specifying the revision number in TortoiseProc.exe,
TortoiseProc.exe /command:checkout <url>