Tips and tricks

Clone disk over ssh

On remotehost:

• have a user 'someuser' you can ssh to with key, so without password. This user must NOT be in wheel/sudoers/admin group!!!

add a line "someuser ALL=(ALL) NOPASSWD: /bin/dd

Then you can run

ssh -C -t someuser@remotehost "dd if=/dev/sdXX" | dd of=/dev/sdXY

Note the "-t" which is required, otherwise you get "sudo: no tty present and no askpass program specified"

Generate random mac address

#!/usr/bin/python
# macgen.py script to generate a MAC address for guest virtual machines
#
import random
#
def randomMAC():
       mac = [ 0x00, 0x16, 0x3e,
               random.randint(0x00, 0x7f),
               random.randint(0x00, 0xff),
               random.randint(0x00, 0xff) ]
       return ':'.join(map(lambda x: "%02x" % x, mac))
#
print randomMAC()

Add disk to VM

cat /proc/scsi/scsi 
Attached devices:
Host: scsi7 Channel: 00 Id: 00 Lun: 00
 Vendor: VMware   Model: Virtual disk     Rev: 1.0 
 Type:   Direct-Access                    ANSI  SCSI revision: 02

In this case your scsi device is 7, so

echo "- - -" > /sys/class/scsi_host/host7/scan

Find your public IP

curl icanhazip.com

or

curl my.ip.fi

and https://ifconfig.co/

Downlowd mp3 from youtube

youtube-dl -x --audio-format mp3 URL

Decimal to binary

echo "obase=2; $var" | bc