Houdini Special characters

Special characters in path definition are:
	 @ - Typically expands to the HOUDINI_PATH. Thus, if the
			 HOUDINI_PATH was set to:
			 $HIP
			 $HFS/houdini
			 $HOME/houdini
			 a path defined as "@/vex" would expand to the paths
			 $HIP/vex
			 $HFS/houdini/vex
			 $HOME/houdini/vex
	 = - This expands to the $HIP variable. This path will always
			 point to where the currently loaded hip resides.
	 & - The ampersand character expands to the "default" path.
			 For example, to add a directory to the a path without
			 worrying about what the default path should actually be,
			 simply set the path to: "/mypath;&". This will search
			 the "/mypath" path first, then search the default path.
	 ^ - Some paths are used for multiple directories. For
			 example, the HOUDINI_VEX_PATH is used to define the
			 search path for Surface, Displacement, Sop, etc. VEX
			 shaders. For VEX, the ^ symbol expands to the shader
			 type. Thus, if the HOUDINI_VEX_PATH variable is set to
			 something like "/usr/local/vex;$HOME/vex/^", when
			 loading Surface shaders, the following directories will
			 be scanned:
			 /usr/local/vex
			 $HOME/vex/Surface
			 and if Sop shaders are being searched for, the
			 following paths will be searched:
			 /usr/local/vex

Houdini command-line Shell :  "hconfig -ap"