Load unpacked Chrome extension programmatically

Yes, although only temporarily *:

chromium --load-extension=path/to/extension

If you want to load multiple extensions, just separate the path by a comma:

chromium --load-extension=path/to/extension,path/to/another/extension

Replace chromium with chrome.exe (or whatever is used to start your Chrome/Chromium browser).

* When you close the browser, and starts it again without the command line argument, then the extension will disappear from the list of installed extensions.

It is possible to install using --load-and-launch-app=path/to/app

it is working for both apps and extensions. (I tested on chrome Version 35.0.1916.153 m)

I am not sure that there is another command for uninstalling. I found this list of chromium commands which is very useful.

3 ways install/use Chrome extensions offline:

Method A: Drag & Drop (Simple)

• Drag & drop ABP.crx on: chrome://extensions to install

Pros: Installs web & non-westore extensions

Cons: Google quickly & permanently disables non-webstore extensions

Method B: Load unzipped extension/7zip to unzip/ABP used as example

• UnZip ABP.crx: C:\ABP
• Load 1: Shortcut: "C:\Program Files (x86)\Google\Chrome\Application\chrome.exe" --load-extension="C:\ABP"
• Load 2: "C:\Program Files (x86)\Google\Chrome\Application\chrome.exe" --load-extension="C:\ABP,C:\IEtab"

Pros: Permanently enables non-webstore extensions, so long as your using custom shortcut

Cons: Extensions only load via custom shortcut

~~~~~~~~~~~~~~~ 3 fixes for extracted extension errors: ~~~~~~~~~~~~~~~

• Won't load: Create shortcut to folder containing manifest file, for example:akkmfdhlogbapbcgojknhfgppcionopk\5.4.7_0

• Metadata: Extension\delete _metadata folder

• Disabled: Open manifest.json with notepad & locate:

"name": "MSG_appName",

"offline_enabled": true,

Create: "offline_enabled": true, if it doesn't exist

Method C: WinRar SFX (Mass install local/non-local profile apps)

Chrome extracts all plugins to:%LocalAppData%\Google\User Data\Default\Extensions

Extensions list by web-store ID. Example: ABP=cfhdojbkjhnklbpkdaibdccddilifddb

ABP needs 3 files: Some extensions may only require 2

• Install all plugins needed, remove all not needed. Exit Chrome.
• Backup: %LocalAppData%\Google to: C:\Backup\Google
• Copy: %LocalAppData%\Google\Chrome\User Data\Default\Extensions to: C:\Google\Chrome\User Data\Default\Extensions
• Copy: %LocalAppData%\Google\Chrome\User Data\Default\secure preferences to: C:\Google\Chrome\User Data\Default\secure preferences
• Copy: %LocalAppData%\Google\Chrome\User Data\Default\Local Extension Settings to: C:\Google\Chrome\User Data\Default\Local Extension Settings
• Create WinRar SFX: Extract C:\Google to: %LocalAppData%\Google

(ABP stores settings: %LocalAppData%\Google\User Data\Default\Local Extension Settings)

Pros: Mass install web & non-webstore apps, from local/nonlocal pc's

Cons: Google quickly & permanently disables non-webstore extensions

When SFX imports secure preferences file, it replaces old extensions/settings with imported

Restore Chrome Backup:

• Exit Chrome & delete %LocalAppData%\Google\Chrome
• Copy C:\Backup\Google to: %LocalAppData%\Google
• Launch Chrome