Script to add a swapfile

swapper.sh

#!/bin/bash
# Creates a swapfile at SWAPFILE.

SWAPFILE=/mnt/swapfile
SWAPSIZE_MB=7168

SWAP_ALREADY_ON=`swapon -s | grep $SWAPFILE`

if [ -e $SWAPFILE ]; then
  if [[ -n $SWAP_ALREADY_ON ]]; then
    echo "$SWAPFILE already exists and activated, skipping."
  else
    echo "$SWAPFILE already exists, activating..."
    swapon $SWAPFILE

    echo "Swap status:"
    swapon -s
  fi

else
  echo "Creating $SWAPSIZE_MB MB swapfile at $SWAPFILE..."
  dd if=/dev/zero of=$SWAPFILE bs=1M count=$SWAPSIZE_MB
  mkswap $SWAPFILE
  swapon $SWAPFILE

  echo "Swap status:"
  swapon -s
fi