The Waf script can be used directly:
$ ./waf
Or, if the executable permissions are not set properly:
$ python waf
By default, the Waf script uncompresses its library in the current directory, in a hidden folder. This means the Waf script must reside in a writable folder. The naming is allow different Waf versions to run from the same folder:
$ ls -ld .waf* .waf-1.5.0-ec924e3f453eb715118b9cc852291170