I am in the directory where the files were downloaded, as per your intruction
BTW their is a typo on your instructions, you spelled bitmian instead of bitmain
I tried with and without the ./ in and out of the installation dir

@Master-VRTJMB:~/bitmain-tools/scripts$ ./l3plus_autotune.py -i 10.0.100.141
/usr/bin/env: ‘python’: No such file or directory
@Master-VRTJMB:~/bitmain-tools/scripts$