Unlock TFS files locked by other users

Common problem we faced in large teams is that, someone locks the file in TFS and which does not allow others to check-in until the locked one, unlocks it. What if the guy who locked is not available or out of team.
Simple scenario is that, we are onsite and offshore model and when particualr release go to production, we normally lock particualr files to make sure anyone check-ing in updates.
But we found sometime that we need to make some change to the lock’ed file and provide build to the Team. In that scenario we have to unlock the locked file

tf.exe is the command-line tool provided by microsoft for commandline activities. In here i just want to address the above mentioned problem

tf.exe lock or tf undo are the commands used for this scenario
syntax:
tf.exe lock /lock:none /workspace: /collection:

– can be replaced with local or TFs path
$/MyProject/TeamBuildTypes/ConfigFiles/BaseConfig.xml

– how do you know, who have locked as this is big team you are working with.
Open the visual studio IDE, after connecting to TFS, Right click on the file you want to checkin
Go to Properites -> Under Status Tab, you can view all the users Edited or locked the file
Get the workspace name and user name ex: ; format
Value would be: mymachine;myuser

– This is straight answer, TFS Project collection url [ this can be optional as you would have already connected. else requird you provide as mentioned in syntax

tf lock /lock:none $/MyProject/TeamBuildTypes/ConfigFiles/BaseConfig.xml /workspace:8100PC019;xxxxxxxx

Output: The operation completed successfully. Because the workspace 8100PC019;Mydomainxxxxxxxx is not on this computer, you must perform a separate get operation in that workspace to update it with the changes that have been made on the server.

Hope this helps.

Refer: Undo: http://msdn.microsoft.com/en-us/library/c72skhw4(v=VS.100).aspx
Lock: http://msdn.microsoft.com/en-us/library/47b0c7w9(v=VS.100).aspx
check the permissions with which unlocking is performed:
http://msdn.microsoft.com/en-us/library/ms252587(v=VS.100).aspx