How do I permanently turn on line numbers in IntelliJ IDEA 14? This post is outdated: how-can-i-permanently-have-line-numbers-in-intellij
Permanently (Ubuntu):
File > Settings > Editor > General > Appearance > Show Line Numbers
For just the current editor: View > Active Editor > Show Line Numbers
You can do it even faster, using the Search Everywhere tool (press Shift twice): type "Show Line Numbers" (or even "line") and the top hit is the switch for permanent line numbers.
There are 2 switches for line numbers, one that has a On/Off switch and works globally, and one without the switch - for the current file. And one more for the Active Editor (current file).
Go to Settings/Editor/General/Appearance and enable Show line numbers to permanently show line numbers for all editors.
The solution with View > Active Editor > Show Line Numbers seems to work only for the active editor (when you close the current tab or open a new file you have to enable it again).
Go to Preferences > Editor > Appearance, and select the Show line numbers check box.
It will turn on the line numbers permanently.
Just right click and enable Lines in Windows. For more info check this link.
IntelliJ IDEA 15.0.3
File > Settings > Editor > General > Appearance > Show Line Numbers
In Android Studio 1.3.2 (a variety of IntelliJ Idea) you can find the "Show line numbers" checkbox under:
Android Studio > Preferences > Editor > General > Appearance
Or, if you type "line numbers" into the main search box you'll be presented with a switch you can set right there.
来源：https://stackoverflow.com/questions/27032622/how-do-i-turn-on-line-numbers-permanently-in-intellij-14