Enable swap with swapfile for Linux.

create-swapfile.sh

#!/bin/bash
# ============================================================
#  Author: 凍仁翔 / chusiang.lai (at) gmail.com
#  Blog: http://note.drx.tw
#  Filename: create-swapfile.sh
#  Modified: 2015-04-22 09:50
#  Description: Enable swap with swapfile for Linux.
#  Reference: 
#   1. Linux Add a Swap File | nixCraft
#    - http://www.cyberciti.biz/faq/linux-add-a-swap-file-howto/
# =========================================================== 

# Size of swapfile.
#
#   1G:  1048576
#   2G:  2097152
#   4G:  4194304
#   8G:  8388608
#  16G: 16777216  (not recommended)
#
SIZE="2097152"

# Create swapfile.
sudo dd if=/dev/zero of=/swapfile bs=1024 count=$SIZE

# Format swapfile.
sudo mkswap /swapfile

# Enable swap.
sudo swapon /swapfile

# Mount swap at boot.
sudo su -c "cat >> /etc/fstab << EOF
/swapfile none swap sw 0 0
EOF"