Create clean-memory

rpi/clean-memory

@@ -0,0 +1,67 @@
+#!/usr/bin/env bash
+
+# Usage:       ./clean-memory
+#                or
+#              bash clean-memory
+# Description: Tries to free the memory (incl. swap)
+# Author:      Patrick Neumann (patrick@neumannsland.de)
+# Platform:    Raspbian GNU/Linux 9.x
+# Version:     1.01
+# Date:        2019-04-30 (first release: 2010-06-01)
+# Link:        (work in progress)
+# License:     GPL3
+# Warranty:    This program is distributed WITHOUT ANY WARRANTY
+
+#-------------------------------------------------------------------------------
+# root-only
+#-------------------------------------------------------------------------------
+if [ $( id -u ) -ne 0 ] ; then
+  echo "You have to be root!"
+  exit 1
+fi
+
+#=== CONFIGURATION (user) ======================================================
+DBG="off"
+
+#-------------------------------------------------------------------------------
+# This is the real magic of this script...
+#-------------------------------------------------------------------------------
+if [ "${DBG}" = "on" ] ; then
+  ### before:
+  echo "Before:"
+  swapon -s
+  free -m
+  echo
+fi
+
+#-------------------------------------------------------------------------------
+# empty cache (1/2)
+#-------------------------------------------------------------------------------
+echo 3 > /proc/sys/vm/drop_caches
+
+#-------------------------------------------------------------------------------
+# empty swap
+#-------------------------------------------------------------------------------
+if grep -E "^/dev/.*swap" /etc/fstab 2>&1 > /dev/null ; then
+  # device (disk or partition)
+  swapoff -a && swapon -a
+fi
+
+if systemctl is-active dphys-swapfile.service 2>&1 > /dev/null ; then
+  # file
+  dphys-swapfile swapoff && dphys-swapfile swapon
+fi
+
+#-------------------------------------------------------------------------------
+# empty cache (2/2)
+#-------------------------------------------------------------------------------
+echo 3 > /proc/sys/vm/drop_caches
+
+if [ "${DBG}" = "on" ] ; then
+  ### after:
+  echo "After:"
+  swapon -s
+  free -m
+fi
+
+exit 0