I use Sublime Text 2 and want a Ruler to be shown in every file with specific line-height. But I have to show it manually in every file.
While the answer by Ross Allen is great, it isn't the most convenient if you find yourself wanting to toggle the rulers on and off or change the width at various points while using Sublime.
Luckily, someone made a Package that allows you to do this.
https://packagecontrol.io/packages/QuickRulers
The package works in both Sublime Text 2 and 3.
⌘ + SHIFT + P)You can access the command (quick_rulers) through several different means, but by default it is loaded in Omnisearch via "QuickRulers: Open Panel". (i.e., Hit ⌘ + SHIFT + P and type "QuickRulers: Open Panel")