Do you have it installed through apt-get?
If not, add the PPA:
sudo add-apt-repository ppa:webupd8team/sublime-text-2 sudo apt-get update and install it:
sudo apt-get install sublime-text (source)
You can then set it as default with xdg-mime if you know the mime types corresponding to the file extensions. For example, to open all .txt files in Sublime Text, run this in terminal:
xdg-mime default sublime-text-2.desktop text/plain To make this work in case you're opening the text file inside some KDE program like Dolphin or Konqueror you will have to copy the corresponding lines under [Default Applications] in ~/.local/share/applications/mimeapps.list and paste them under [Added Associations] in the same file. So your ~/.local/share/applications/mimeapps.list would look like this if you had only this one .txt associaton:
[Default Applications] text/plain=sublime-text-2.desktop [Added Associations] text/plain=sublime-text-2.desktop