XML : Starting Ant build from bash script: build.xml does not exist

I am creating a bash script in Linux (ubuntu) that starts an ant build from a build.xml file, located in another directory. My folder structure looks like this:

  myBashScript.sh     /project56          /http           build.xml    

When I try to call this build file from myBashScript.sh I get the following error:

"Buildfile project56/http/buildfile.xml does not exist!"

I tried the following:

  sudo ant -buildfile project56/http/build.xml    sudo ant -v project56/http/build.xml    sudo ant -v fullPathStartingFromHome/build.xml    

But I keep getting this error. The funny thing is, when I try to invoke ant (using the first option listed above) from the terminal in the same location that myBashScript.sh is in, the build starts fine.

Can someone help me with this?

Thanks in advance,

Robert