[root]#ant

Unknown argument: -cp
ant [options] [target [target2 [target3] …]]
Options:
-help, -h              print this message
-projecthelp, -p       print project help information
-version               print the version information and exit
-diagnostics           print information that might be helpful to
diagnose or report problems.
-quiet, -q             be extra quiet
-verbose, -v           be extra verbose
-debug, -d             print debugging information
-emacs, -e             produce logging information without adornments
-lib <path>            specifies a path to search for jars and classes
-logfile <file>        use given file for log
-l     <file>                ”
-logger <classname>    the class which is to perform logging
-listener <classname>  add an instance of class as a project listener
-noinput               do not allow interactive input
-buildfile <file>      use given buildfile
-file    <file>              ”
-f       <file>              ”
-D<property>=<value>   use value for given property
-keep-going, -k        execute all targets that do not depend
on failed target(s)
-propertyfile <name>   load all properties from file with -D
properties taking precedence
-inputhandler <class>  the class which will handle input requests
-find <file>           (s)earch for buildfile towards the root of
-s  <file>           the filesystem and use it
-nice  number          A niceness value for the main thread:
1 (lowest) to 10 (highest); 5 is the default

I did a google search on “ant Unknown argument: -cp” and ended up with a pretty decent number of hits. But unfortunately none of them seem to offer a simple and elegant solution to my problem. The solution ranged from deleting a file from /etc directory to changing the ant script itself, which were definately not acceptable due to the fact that these builds were working perfectly before. After some digging around I found why this occured in my environment. Apparently Ant does not like if the ANT_HOME is different from the location of ANT’s bin in the PATH variable. For example, I had my ANT_HOME as

echo $ANT_HOME

/opt/ant170

And the PATH is set to point to a different version of ANT as,

echo $PATH

/usr/kerberos/sbin:/usr/kerberos/bin:/sbin:/bin:/usr/sbin:/usr/bin:

/opt/1.6.2a/bin:/opt/java/1.5/bin

Setting my PATH to the right ANT’s bin directory fixed the problem..