Calculate percentage of free memory using bash scripts in linux

Question

I would like to calculate the percentage of free memory using Linux bash shell scipts.

Example:
bash-4.1$ free
              total       used       free     shared    buffers     cached
 Mem:      12223100   11172812    1050288        316     714800     629944
 -/+ buffers/cache:    9828068    2395032
 Swap:      6266872    5852824     414048

Ex. (1050288/12223100) * 100 = %free memory-I want to do this using scripts.

Thanks Puspa

d34db33f · Accepted Answer · 2016-11-04 16:44:53Z

5

memfree=`cat /proc/meminfo | grep MemFree | awk '{print $2}'`; 
memtotal=`cat /proc/meminfo | grep MemTotal | awk '{print $2}'`; 
bc -l <<< "$memfree * 100 / $memtotal"

the proc/meminfo file displays everything you should need about memory.

You use grep to isolate the line about Free Memory and Total memory, and store it in variables. Then you use bc -l for the float division.

EDIT: If there is no bc installed, you may use echo :

echo $(($memfree.0 * 100 / $memtotal))

edited Nov 4, 2016 at 16:44

answered Nov 3, 2016 at 9:53

d34db33f

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4 Comments

XYZ Over a year ago

Thanks You.I am using bash shell in Linux.There is no bc installed.what is the alternate way ?

d34db33f Over a year ago

You can use echo then :

Mark Setchell Over a year ago

You invoke a total of 7 processes here (2 cat, 2 awk, 2 grep, 1 bc) when it can all be done with a single awk. Mmmm...

Mark Setchell Over a year ago

This might be better... awk '/MemFree/{free=$2} /MemTotal/{total=$2} END{print (free*100)/total}' /proc/meminfo

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