redirect frintf to a variable

Shell Programming and Scripting
1

how to redirect printf to a variable

2 
$ a=$(printf "%08x" 22)
$ echo $a
00000016
3

this is not working :frowning:

here is my code for

#!/bin/bash
FREE=`free -m | awk '/^Mem:/	{ printf( "%s\n", $4 ); }'`
USED=`free -m | awk '/^Mem:/	{ printf( "%s\n", $3 ); }'`
TOTAL=`expr $FREE + $USED`
awk -v TOTAL=$TOTAL -v FREE=$FREE -v USED=$USED '
BEGIN {
 printf "FREEPER: %3.2f%%\n", FREE / TOTAL * 100
 printf "USEDPER: %3.2f%%\n", USED / TOTAL * 100
 exit
}'

i would like to pass each printf output to a variable

4

I don't follow your explanation, but...

#!/bin/bash
free -m | awk '/^Mem:/ { f+=$4; u+=$3 } END {t=f+u; printf("FREEPER: %3.2f\n USEDPER: %3.2f\n", f/t*100, u/t*100)}'
5

this is really simplified but any chance to pass FREEPER and USEDPER to two variables

6

it's possible:

free -m > /tmp/foo$$; eval $(awk '/^Mem:/ { f+=$4; u+=$3 } END {t=f+u; printf("FREEPER=%3.2f\nUSEDPER=%3.2f\n", f/t*100, u/t*100)}' /tmp/foo$$); rm /tmp/foo$$; echo $USEDPER

What is it that you're after?
Most likely you don't have to pass the variables back to shell - everything could be down within awk itself...

7

to make this script run in continues time intervals
if for certain time span the USEDMEM is high then generate an ALERT
also avoiding using cron job

8

something to start with...

#!/bin/bash

typeset -i thrF=80
typeset -i thrU=90

typeset -i sleepPeriod=10

while :
do
  free -m | awk -f tF=${thrF} -v "${thrU}"'/^Mem:/ { f+=$4; u+=$3 } END {t=f+u; freeper=f/t*100; usedper=u/t*100
; if (freep>thrF) printf("freeper > thresholdFree\n"); if (usedp>thrU) printf("usedper > thresholdUsed\n")}'
  sleep "${sleepPeriod}"
done
9

It is definitely working. I copy and pasted the command and its result.

You should have explained in your posting you were expecting awk printf to be redirected in a variable. Without context, it's hard to guess.

Here is probably what you are looking for, although there are a lot of potential optimizations:

FREE=`free -m | awk '/^Mem:/    { printf( "%s\n", $4 ); }'`
USED=`free -m | awk '/^Mem:/    { printf( "%s\n", $3 ); }'`
TOTAL=`expr $FREE + $USED`
FREEPER=$(awk -v TOTAL=$TOTAL -v FREE=$FREE -v USED=$USED 'BEGIN {printf "%3.2f%%",FREE/TOTAL*100;exit}')
USEDPER=$(awk -v TOTAL=$TOTAL -v FREE=$FREE -v USED=$USED 'BEGIN {printf "%3.2f%%",USED/TOTAL*100;exit}')