Hello,
There is a little mistake on this page : http://atavismonline.com/wiki/doku.php/setting_up_the_server
The mistake is on the last line : Note: If you are running on Ubuntu and having trouble starting the server you may need to delete the top line in both auth.sh and world.sh.
Actually, you don't need to delete this line. Thing is, the shebang (the line starting with #!) in world.sh and auth.sh is actually incorrect : you are using bash's syntax but asking for sh interpreter to read it. In most modern linux system, /bin/sh is actually an alias to /bin/bash but is used to trigger a "strict mode" on bash, removing it's own functionnality to better emulate sh's traditionnal ones.
So, if you want to have the server working on linux and have this error :
./auth.sh: 21: ./auth.sh: Syntax error: "(" unexpected
Just change the shebang (the first line) of auth.sh and world.sh to this :
#!/bin/bash
And everything will work. A better solution would be to actually replace in atavism's original source code the shebang. I didn't test but i'm 99% sure it will also work on cygwin, and it will have the correct behavior.