Generate Random MAC-Address

randomMac-bash.sh

#!/bin/bash
#
# Generate Random MAC-address
#
# Locally administered:
#   X2-XX-XX-XX-XX-XX
#   X6-XX-XX-XX-XX-XX
#   XA-XX-XX-XX-XX-XX
#   XE-XX-XX-XX-XX-XX
#
# Reference:
#   https://en.wikipedia.org/wiki/MAC_address
#
# Original Source:
#   https://gist.github.com/ggrandes/33a27eb00f49b94fcb0dfeb597226bab
#
randomMac () {
  local l=$(tr -dc '26ae' < /dev/urandom | dd bs=1 count=1 status=none)
  local r=$(tr -dc '0-9a-f' < /dev/urandom | dd bs=11 count=1 status=none)
  echo "${r:0:1}${l}:${r:1:2}:${r:3:2}:${r:5:2}:${r:7:2}:${r:9:2}"
}
randomMac

randomMac-sh.sh

#!/bin/sh
#
# Generate Random MAC-address
#
# Locally administered:
#   X2-XX-XX-XX-XX-XX
#   X6-XX-XX-XX-XX-XX
#   XA-XX-XX-XX-XX-XX
#   XE-XX-XX-XX-XX-XX
#
# Reference:
#   https://en.wikipedia.org/wiki/MAC_address
#
# Original Source:
#   https://gist.github.com/ggrandes/33a27eb00f49b94fcb0dfeb597226bab
#
case "$1" in
  awk)
    awk '
BEGIN {
  # generate random mac
  srand();
  for (i = 0; i <= 48; i++) {
    hex[i]=int(rand() * 10 % 2);
  }
  hex[6]=1; # local admin
  hex[7]=0; # unicast
  # convert to string
  mac="";
  for (i = 0; i < 48; i+=4) {
    v=0;
    for (j = 0; j < 4; j++) {
      if (hex[i+j] == 1) {
        v += (2**(3-j));
      }
    }
    if ((i > 0) && (i % 8 == 0)) {
      mac=sprintf("%s:%x", mac, v);
    } else {
      mac=sprintf("%s%x", mac, v);
    }
  }
  print mac;
}
'
  ;;
  hexdump)
    hexdump -n 6 -e '1/1 "%02x:"' < /dev/urandom | sed -E -e 's|:$|\n|g' -e "s|^(.).|\1$(tr -dc '26ae' < /dev/urandom | dd bs=1 count=1 status=none)|g"
  ;;
  xxd)
    xxd -l 6 -p /dev/urandom | sed -E -e 's|(..)|\1:|g' -e 's|:$||g' -e "s|^(.).|\1$(tr -dc '26ae' < /dev/urandom | dd bs=1 count=1 status=none)|g"
  ;;
  *)
    echo "$0 <awk|hexdump|xxd>"
  ;;
esac