Regarding Swap memory usahe monitot via shell script

pan64 · 06-17-2020, 02:08 AM

Quote:

Originally Posted by ncnaveen_arasu

Hi

thanks for the suggestion. we are in restricted environment where third party application/software cant be installed.
or else would have been tried.
thanks for advice,will be try using it in other environment.

you do not need to install shellcheck, it is an online tool which can be used within a browser. Or as a standalone app without installation, if downloaded.
Anyway it is much faster than posting to a forum and waiting for an answer.

Last but not least you need to learn and understand what's going on, otherwise you will hardly be able to implement anything. Go step by step.
For example based on post #13 you can check what will be stored in the variable swap.
Next you can check how an if construct works and how can you write a conditional expression.

TB0ne · 06-17-2020, 08:08 AM

Quote:

Originally Posted by ncnaveen_arasu

Hi New to forum and Linux too..and was not knowing that i can show gratitude by clicking on green button. So was marking it as helpful.
Thanks for the suggestion.

No need, but you do need to pay attention and apply what you're told. This thread was almost IDENTICAL to your other thread, and you've been told about the 'team' before as well.

rnturn · 06-17-2020, 12:36 PM

Quote:

Originally Posted by ncnaveen_arasu

Hi Team,

trying to monitor swap memory usage from below script.

#! /bin/bash

swap=$(free | awk '/Swap/{printf ("%.2f%"), $3/$2*100}')

if [ $swap -lt 20% ]
then
echo "OK - Swap Memory at $swap %"
exit 0
elif [[ $swap -ge 20% && $swap -lt 40% ]]
then
echo "Warning - Swap Memory at $swap %"
exit 1
elif [ $swap -ge 40% ]
then
echo "CRITICAL - Swap Memory at $swap %"
exit 2
else
echo "UNKNOWN - unable to retrieve Swap Memory usage"
exit 3
fi

================================================================

But getting error as below. Not sure where am doing wrong. Can someone please assist.

./swap.sh: line 5: [: 7.40%: integer expression expected
./swap.sh: line 9: [[: 7.40%: syntax error: invalid arithmetic operator (error token is ".40%")
./swap.sh: line 13: [: 7.40%: integer expression expected
UNKNOWN - unable to retrieve Swap Memory usage

Thanks

The tests you are doing ("-ge") are for integers. Omit the percent sign from the output of your printf() and change the tests to something like:

Code:

if [ $SWAP -ge 90 ]; then
    echo "Yikes"
fi

Or use a scripting language other than shell. Perl and/or Python can deal with floating point numbers w/o problems.

HTH...

JeremyBoden · 06-17-2020, 02:04 PM

It's not really necessary to do all this $SWAP stuff - Linux would tell you if you if things had got critical.
You would most likely get only a few seconds to identify and kill a runaway process before the machine crashes.

rtmistler · 06-18-2020, 05:00 PM

As pan64 points out, you can syntax check using online tools.

In my signature is a blog about bash debugging, it also contains bash references.

There's a ton you can do just using various coding and debugging techniques in your script.

As TB0ne notes, you have to do these diagnostics on your own to learn them. My thought processes when I hit a coding challenge is that I remind myself that a lot of people can likely do this stuff nearly in their sleep, and that it is not rocket science, so I can do it myself.