Setup a Swap file on a server where swap is not found.

gistfile1.sh

if [ ! -d "/opt" ];then
  mkdir /opt
fi


if [ ! "$(swapon -s | grep -v Filename)" ];then
  cat > /opt/swap.sh <<EOF
#!/usr/bin/env bash
if [ ! "\$(swapon -s | grep -v Filename)" ];then
SWAPFILE="/tmp/SwapFile"
if [ -f "\${SWAPFILE}" ];then
  swapoff -a
  rm \${SWAPFILE}
fi
dd if=/dev/zero of=\${SWAPFILE} bs=1M count=2048
mkswap \${SWAPFILE}
swapon \${SWAPFILE}
fi
EOF

  chmod +x /opt/swap.sh
  /opt/swap.sh
fi

if [ -f "/opt/swap.sh" ];then
  if [ ! -f "/etc/rc.local" ];then
    touch /etc/rc.local
  fi

  if [ "$(grep 'exit 0' /etc/rc.local)" ];then
    sed -i '/exit\ 0/ s/^/#\ /' /etc/rc.local
  fi
  
  if [ ! "$(grep 'swap.sh' /etc/rc.local)" ];then 
    echo "/opt/swap.sh" | tee -a /etc/rc.local
  fi
  
  chmod +x /etc/rc.local
fi