On CentOS 6, installed Liferay 6.1 ce bundled with tomcat 7.0.23.

In opt/liferay/tomcat/bin run ./startup.sh and get:

Neither the JAVA_HOME nor the JRE_HOME environment variable is defined
At least one of these environment variable is needed to run this program

The default setenv.bat is:

if exist "%CATALINA_HOME%/jre1.6.0_20/win" (
if not "%JAVA_HOME%" == "" (
set JAVA_HOME=/jre1.6.0_20/win
)

set "JRE_HOME=%CATALINA_HOME%/jre1.6.0_20/win"
)

set "JAVA_OPTS=%JAVA_OPTS% -Dfile.encoding=UTF8 -Djava.net.preferIPv4Stack=true -Dorg.apache.catalina.loader.WebappClassLoader.ENABLE_CLEAR_REFERENCES=false -Duser.timezone=GMT -Xmx1024m -XX:MaxPermSize=256m"

I have tried several different paths for each value in .bat with no success.

Any ideas? What am I missing?

Do you have JDK installed on your CentOS? Be sure to replace pre-installed OpenJDK with Oracle JDK because OpenJDK may not work properly.

Yes, I have it installed at /usr/java/jdk1.7.0 and set the path in /opt/liferay/tomcat/setenv.bat to

if exist "%CATALINA_HOME%/jre1.6.0_20/win" (
if not "%JAVA_HOME%" == "" (
set JAVA_HOME=/usr/java/jdk1.7.0/

set "JRE_HOME=%CATALINA_HOME%/jre1.6.0_20/win"
)

set "JAVA_OPTS=%JAVA_OPTS% -Dfile.encoding=UTF8 -Djava.net.preferIPv4Stack=true -Dorg.apache.catalina.loader.WebappClassLoader.ENABLE_CLEAR_REFERENCES=false -Duser.timezone=GMT -Xmx1024m -XX:MaxPermSize=256m"

Do not use JDK 1.7.

Besides, you're running a Unix variant, you shouldn't be using the .bat guys to begin with. Use the .sh bash scripts...

Got it ... so use 1.6?

1.6 with the unix scripts, yes.

Yes, configure your environment in setup.sh instead of setup.bat. Use ./startup.sh to execute.
How were you executing startup.bat on CentOS anyways? I hope that you're not going to tell us that you have Windows installed as a vm and trying to run liferay in that. :-)

Looks like that was the issue ... once I installed 1.6 it fired right up. Interesting that I read many places that people were using 1.7, but it must have been with another bundle or EE. Anyhow ... thanks.

Same with the EE version. Liferay.com has stated they still do not support 1.7 because of known problems which they have not fixed.