How can I check the version of a Liferay instance?

Question

I have several instances of Liferay Portal (bundled with Apache Tomcat 5.5.x/6.x) and I need to know how to check the version of those Liferay instances

Answer 1

In the enterprise edition, in addition to the installed package (Dima's answer) you can update Liferay using service packs. Here is how to know what service pack level you have installed:

cd $LIFERAY/patching-tool
./patching-tool.sh info

It will show something like this:

Loading product and patch information...
Product information:
  * installation type: binary
  * build number: 7010
  * service pack version:
    - available SP version: 5
    - installable SP version: 5
  * patching-tool version: 2.0.6
  * time: 2018-01-31 08:37Z
  * plugins: Demo 201802, Space 1-2 Columns 50/50 Limited, Space 50/50 Width Limited, Space Program, Space Program Theme

Currently installed patches: de-30-7010

Available patches: de-22-7010, de-30-7010

Detailed patch list: 
  [ -] de-22-7010 :: Currently not installed; Won't be installed: de-30 contains the fixes included in this one :: Built for LIFERAY
  [*I] de-30-7010 :: Installed; Will be installed. :: Built for LIFERAY

The important line is Currently installed patches: de-30-7010.
Then you know that you have Service Pack 30.