[ubuntu] What is the proper tool to use for editing files on a server?

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http://ubuntuforums.org – I have a gaming server set up and running client software 24/7. This prevents me from editing the configuration files while the client is running. The server is connected to a switch which also connects another computer to the internet. What would be the proper software to use if I want to edit files on the server without interrupting the client? I have looked at Samba, SSH, and Screen, but I'm not entirely sure which one would be the best tool for the job. Any ideas? (HowTos)