I would like to reinstall my operating system and keep the IntelliJ IDEA settings (like colors, indents, inspections, etc.). Is there a way to save my settings to keep them during operating system reinstalling?
2020.01 version and above
File → Manage IDE Settings → Export settings
Below 2020.01
File → Export Settings.
You can disable the "Settings repository" under File --> Settings --> Plugins but this doesn't seem to make a blind bit of difference to your ability to export settings "manually".
In the later versions it seems like you should go with either configuring a settings repository or using IDE Settings Sync plugin. More information here:
IntelliJ IDEA lets you share your settings between different instances of your IDE. This helps you recreate a comfy working environment if you are working from different computers and spare the annoyance of things looking or behaving differently from what you are used to.
You can share your settings in one of the following ways:
By configuring a settings repository. This allows you to sync any configurable components (except for the list of enabled and disabled plugins), but requires setting up a Git repository with the settings you want to share. This option is useful if you want to implement the same settings among your team-members.
By using the IDE Settings Sync plugin. It utilizes the JetBrains server, so no additional configuration is required. Synced settings are linked to your JetBrains Account, so they will not be available to other users. The settings you can sync include: IDE themes, keymaps, color schemes, system settings, UI settings, menus and toolbars settings, project view settings, editor settings, code completion settings, parameter name hints, live templates, code styles, and the list of enabled and disabled plugins.