Get free memory numbers as variables in script

bomberb17 · 12-04-2022, 07:07 PM

I want to use all number outputs from

Code:

free -m

as variables in a script.

My script looks like this

Code:

#!/bin/bash

READ_MEM=$(free -m)
USED_MEM_VALUE=$READ_MEM (|awk '{print $9}')
echo $READ_MEM
echo $USED_MEM_VALUE

but the output is as follows

Code:

./mem.sh
./mem.sh: line 4: READ_MEM: command not found
total used free shared buff/cache available Mem: 1845 287 322 3 1235 1370 Swap: 0 0 0

What am I doing wrong? (i.e. the value of USED_MEM_VALUE should be 287 in this example, but I get an empty line)

syg00 · 12-04-2022, 07:35 PM

There must be a million ways to get that value, that would be one of the more esoteric.

You want to use the value of READ_MEM as input - just like you use it in the next line.

michaelk · 12-04-2022, 08:17 PM

And that would be...

Code:

USED_MEM_VALUE=$(echo $READ_MEM | awk '{print $9}')

bomberb17 · 12-04-2022, 09:17 PM

Quote:

Originally Posted by michaelk

And that would be...

Code:

USED_MEM_VALUE=$(echo $READ_MEM | awk '{print $9}')

Thanks!

Dell3185 · 12-04-2022, 10:53 PM

https://serverfault.com/questions/10...tion-of-used-m

https://www.inmotionhosting.com/supp...-memory-usage/

MadeInGermany · 12-06-2022, 12:39 PM

You can get all values in one go

Code:

#!/bin/bash
{
read x
read x memtotal memused memfree memshared membuf memavail x
read x swptotal swpused swpfree x
} < <( free -m )
echo "memused $memused"

Each read command reads one line.
Each field reads into a variable. Extraneous fields are read into the last variable.

The <( ) is a "process substitution"; the { code } runs in the main shell.

In contrast, a pipe:

Code:

free -m |
{
read x
read x memtotal memused memfree memshared membuf memavail x
read x swptotal swpused swpfree x
echo "memused $memused"
}
echo "memused $memused"

Here the { code } runs in a subshell; the variables are not copied back to the main shell.