Notice I said platform independance. Hint: I'm a Linux guy. Basically what I want is a situation where every mod is platform independant without extra work from the author - which makes assumptions about what the OS will and won't do not good.
On all platforms, commands from the $PATH are executed from the $PWD without need to specifying it. Hint: under Linux, "rm" is an executable inside the path (as is cp, mv, rename and a slew of other common commands). If you do rm somefile, it removes somefile from the $PWD, rather than from the path containing "which rm". With WeiDU, it's the same thing: it installs in $PWD rather than in /bin or wherever you put weidu (or whatever you called it).
If you take the install.bat I posted above, rename it to install.sh, make it executable, add it into the $PATH (preferabily, but not needed, in the same dir as weidu), replace weidu.exe with weidu, and replace %1 with $1, it will work: 1 copy of weidu and 1 simple script, and this will allow to install mods in any dir.
Note: I am a Windows guy, with some use of Cygwin and Linux, mostly command-line bound, so I know what I'm talking about.