Sap333

1. Set paravirtualization provider KVM for Linux (since 2.6.25) guests and Hyper-V for Windows (since Windows 7) guests.
2. Set ICH9 chipset for guest machine (may have some issues).
3. Enable nested paging.
4. Enable VT-x virtualzation. Notice: Runing both software and hardware virtualization simlutaneously slows down the emulation.
5. Enable "Virtual Processor Identifiers" (VPIDs). Has large performance impact but guest's CPU may depend on hosts's CPU:
    VBoxManage modifyvm VM_NAME --vtxvpid on
6. Enable large pages - gives up to 5% performance boost:
    VBoxManage modifyvm VM_NAME --largepages on
7. Enable SSE 4.1 and 4.2 for guest VM (an experemental option!):
   VBoxManage setextradata VM_NAME VBoxInternal/CPUM/SSE4.1 1

Sap333

#!/bin/bash
# I need a job!

declare VERSION='1.2' # Script version.

function eexit {
	local EXITCODE=2; [ "$1" -eq "$1" ] 2>/dev/null && EXITCODE="$1" && shift 
	[ $# -ne 0 ] && echo 'Error:' "$@" >&2
	exit "$EXITCODE" ; exit 1
}

Sap333

#!/bin/bash

function printUsage {
echo "Usage:
  $(basename "${BASH_SOURCE[0]}") <SRC_DIR> <DST_DIR>
  Makes a recursive copy of <SRC_DIR> to <DST_DIR> using harlinks and avoiding softlinks.
If <DST_DIR> exists then creates there a subdirectory with name of <SRC_DIR>. Otherwise,
creates <DST_DIR> and uses it as a destination directory." >&2
exit $0 
}

Sap333

#!/usr/bin/python3
# It is for Python3 but may work for modern 2.x versions as well.

import os, signal, atexit

# Signletone which is made as a class with static methods.
# The "init()" method must be called before any child process are created.
# "killAllChildrenOnce" or "killAllChildren" methods could be called 
# any time to kill all child processes.
#   Creates a new process group during initialization and uses it to send