Download more RAM script

download-ram.sh

@@ -0,0 +1,149 @@
+#!/usr/bin/env bash
+
+download_ram() {
+
+  local requested_size="$1"
+
+  echo "Downloading $requested_size GiB of RAM"
+
+  local total_needed=$(( requested_size + 4 ))
+
+  if check_root_space "$total_needed"; then
+    echo ""
+  else
+    exit 1
+  fi
+
+  if actually_download_the_ram "$requested_size"; then
+    echo "Done, run (sudo) swapon --show to see your new RAM"
+  else
+    echo "Failed"
+    exit 1
+  fi
+}
+
+actually_download_the_ram() {
+
+  local size_gb="$1"
+  local dir="/var/swap"
+
+  # Create directory to save swapfiles
+  mkdir -p "$dir" || {
+    echo "Failed to create $dir" >&2; return 1;
+  }
+
+  # Find the next available swapfile name
+  local i=0
+  local swapfile
+  while :; do
+    swapfile="$dir/swapfile$i"
+    [ -e "$swapfile" ] || break
+    i=$((i + 1))
+  done
+
+  echo "Downloading $swapfile (${size_gb}G) of RAM"
+
+  # Use fallocate (or dd in case no fallocate is installed) to create swapfile
+  if ! fallocate -l "${size_gb}G" "$swapfile" 2>/dev/null; then
+    echo "fallocate failed, falling back to dd (this may take a while)..."
+    if ! dd if=/dev/zero of="$swapfile" bs=1G count="$size_gb" status=progress; then
+      echo "fallocate/dd failed in creating swapfile" >&2
+      rm -f "$swapfile"
+      return 1
+    fi
+  fi
+
+  # Set file to read and write
+  chmod 600 "$swapfile" || {
+    echo "chmod failed" >&2;
+    rm -f "$swapfile"; return 1;
+  }
+
+  # Turn the file to swap type
+  if ! mkswap "$swapfile"; then
+    echo "mkswap failed" >&2
+    rm -f "$swapfile"
+    return 1
+  fi
+
+  # Run swapon to enable swap
+  if ! swapon "$swapfile"; then
+    echo "swapon failed" >&2
+    return 1
+  fi
+
+  # Check if swap is running and write into fstab file
+  if swapon --show | awk 'NR>1 {print $1}' | grep -qx "$swapfile"; then
+    echo "Successfully 'downloaded' ${size_gb}G of RAM into: $swapfile"
+    if ! grep -q -E "^[[:space:]]*${swapfile}[[:space:]]" /etc/fstab; then
+      printf "%s\n" "${swapfile} none swap defaults 0 0" >> /etc/fstab
+    else
+      echo "Entry for $swapfile already exists in /etc/fstab, not adding duplicate"
+    fi
+    return 0
+  else
+    echo "Swapfile created but not active. Check 'swapon --show'" >&2
+    return 1
+  fi
+
+}
+
+check_root_space() {
+
+  local need_gib=$1
+  local free_gib
+
+  free_gib=$(df -B1G --output=avail / | tail -n1 | tr -d ' ')
+
+  if (( free_gib >= need_gib )); then
+    return 0
+  else
+    echo "Your system does not have enough space to download the RAM"
+    echo "Need at least ${need_gib}GiB free, but only ${free_gib}GiB is available." >&2
+    return 1
+  fi
+
+}
+
+# -- Start of Script --
+
+# Check if ran as sudo
+if [[ "$EUID" -ne 0 ]]; then
+    echo "This script must be run as root (try: sudo $0)" >&2
+    exit 1
+fi
+
+# Check if system is mounted on a ext4 filesystem
+fs_type=$(findmnt -no FSTYPE / 2>/dev/null)
+if [[ "$fs_type" != "ext4" ]]; then
+    echo "Error: /var is on '$fs_type'. This script only supports systems mounted on ext4." >&2
+    exit 1
+fi
+
+# Message + handle input
+echo "Please select how much RAM you want to download:"
+echo "1) 4GiB of RAM"
+echo "2) 8GiB of RAM"
+echo "3) 16GiB of RAM"
+echo "Plese note you need at least the chosen amount of space on your drive + 4GiB"
+echo ""
+
+read -r -p "Enter your choice (1-3): " choice
+
+case "$choice" in
+  1)
+    value=4
+    ;;
+  2)
+    value=8
+    ;;
+  3)
+    value=16
+    ;;
+  *)
+    echo "Invalid choice."
+    exit 1
+    ;;
+esac
+
+download_ram "$value"