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@inthuriel inthuriel/freemem.sh
Last active Apr 24, 2018

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Bash script to clean system caches in Linux OS
#!/bin/sh
###########################################################################
# use freemem [lvl] [limit to run /num//unit/] [limit to 0- total 1- cache] #
# example usage ./freemem 3 3G 0 #
# author Mikolaj 'Metatron' Niedbala #
# licenced GNU/ GPL #
###########################################################################
echo $1 $2 $3
if [ "$1" -gt "3" ]; then
echo "Cache cleaning level out of range"
exit 1
fi
#get total memory
TOTALMEM=`cat /proc/meminfo | grep MemTotal | grep -o "[0-9]\{1,\}"`
#get free memory
MEMFREE=`cat /proc/meminfo | grep MemFree | grep -o "[0-9]\{1,\}"`
#calculate used memory
if [ "$3" -eq "0" ]; then
USEDMEM=$(($TOTALMEM - $MEMFREE))
elif [ "$3" -eq "1" ]; then
USEDMEM=`cat /proc/meminfo | grep ^Cached | grep -o "[0-9]\{1,\}"`
else
echo "Define if calculate form whole memory or cached only"
exit 1
fi
#calculate limit
UNITMEM=`echo $2 | tr '[:upper:]' '[:lower:]' | grep -o "[a-z]\{1,\}$" | awk 'BEGIN { FS = "" } ; { print $1 }'`
LIMITMEM=`echo $2| grep -o "[0-9]\{1,\}"`
if [ "$LIMITMEM" -le "0" ]; then
echo "Memory limit is out of range"
exit 1
fi
if [ `echo $UNITMEM | grep -v "[k|m|g]"` ]; then
echo "Unit is out of scope, should be [k|m|g]"
exit 1
fi;
case $UNITMEM in
"g") LIMITMEM=$(($LIMITMEM * 1024 * 1024)) ;;
"m") LIMITMEM=$(($LIMITMEM * 1024)) ;;
"k") LIMITMEM=$(($LIMITMEM)) ;;
*) LIMITMEM=$(($LIMITMEM)) ;;
esac
#cache clean or exit
if [ "$USEDMEM" -gt "$LIMITMEM" ]; then
echo "Memory limit exceed, droping caches."
sync; echo $1 > /proc/sys/vm/drop_caches
exit 0
else
echo "Memory is within defined limits. Nothing to do, exiting."
exit 0
fi;
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