Sooner or later, you will need to modify a file you have already uploaded to the cluster. One obvious option is to modify the file locally on your laptop and then re-upload it with SCP or another tool. This of course lacks convenience...
Other options include using a text editor with remote editing capabilities such as SublimeText, TextMate, Notepad++, TextWrangler, Atom, etc., or using the remote editing features of FileZilla, Cyberduck, etc. or mounting the remote filesystem with SSH-FS.
All these approaches have pros and cons, but the quickest and most efficient is to learn how to use a terminal-based editor such as Vim, Emacs, or Nano, or mcedit, ne, slap, micro, pico, Joe, mped, etc. You most probably will find Vim, Emacs and Nano preinstalled on every Linux system you can access. So learning one of those three is a must.
If you want super editing powers (read features), try both Vim and Emacs ; they are so different that you’ll soon feel one of them is your preferred choice. Then learn it inside out.
If you want very quick time to market (read ease of use), go for Nano or Pico.