- add build doc

- improve terminal doc

DOCS.md

@@ -12,6 +12,7 @@
 - [How do I run VSCodium in portable mode?](#portable)
 - [How do I press and hold a key and have it repeat in VSCodium?](#press-and-hold)
 - [How do I open VSCodium from the terminal?](#terminal-support)
+  - [From Linux .tar.gz](#from-linux-targz)
 
 ## <a id="disable-telemetry"></a>Getting all the Telemetry Out
 
@@ -135,6 +136,7 @@ $ defaults write com.visualstudio.code.oss ApplePressAndHoldEnabled -bool false
 
 ## <a id="terminal-support"></a>How do I open VSCodium from the terminal?
 
+For MacOS and Windows:
 - Go to the command palette (View | Command Palette...)
 - Choose `Shell command: Install 'codium' command in PATH`.
 
@@ -148,3 +150,9 @@ This allows you to open files or directories in VSCodium directly from your term
 ```
 
 Feel free to alias this command to something easier to type in your shell profile (e.g. `alias code=codium`).
+
+On Linux, when installed with a package manager, `codium` has been installed in your `PATH`.
+
+### <a id="from-linux-targz"></a>From Linux .tar.gz
+
+When the archive `VSCodium-linux-<arch>-<version>.tar.gz` is extracted, the main entry point for VSCodium is `./bin/codium`.