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

First off, you should inspect those errors.

Has it not occurred to you that they are at every line where you've placed a test against a percentage?

Therefore you could search for information about how to compare numbers in bash.

Percentages are not valid, at least not with these types of comparisons, instead you'd compare strings. But if you don't need to, then instead remove the percent sign and just compare the integers.

This all depends on what is in the variable swap.

This also appears to not be the code where you've seen the errors, there are not 3 repetitions of the string "40%" in lines which are 4 apart from each other.

Anyways, that's a fundamental problem with your script, your compares. Suggest you print out the variable $swap to see what it contains as a debug before you code your comparisons.

3 members found this post helpful.

My additional point being, if you just take one piece of information where I say remove the percent sign in your compares, that is not necessarily the solution, in fact may be very unlikely. It's not helpful if you do just that and then reply "it didn't work", so that point is to debug the script so you know what comparison works correctly.

There are a few things you can change for your awk statement to make your life easier.

2 members found this post helpful.

I would suggest you yo use www.shellcheck.net to check your script. (it will also help you to solve the problems found).

5 members found this post helpful.

[QUOTE=pan64;6133065]I would suggest you yo use www.shellcheck.net to check your script. (it will also help you to solve the problems found).[/QUOTE

Hi thanks for posting the useful tool to check script which i was not aware of.
It did fix the issue.
Thanks for it.

1 members found this post helpful.

Hi Team,

As script was testing at "OK" threshold before. but now one of the host crossed ok and reached "warning" level. but still getting ok status as below.
[test ~]$ ./swap_memory_health_check.sh
OK - Swap Memory at 25.40%

Code used is below. seems good with if loop but not sure where am doing wrong.

#! /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

Please assist.

see post #5 and try that useful tool. And also please use code tags.

1 members found this post helpful.

Don't have VM right now for Linux but what is the output of:

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

Is the output of $swap equals to 20%?

If yes, then you should compare as string. -lt then is for comparing numbers. 20% -is considered a string because of percent sign

try like these instead:

if [ "$swap" -eq "20%" ]

Good luck!

1 members found this post helpful.

Hi JJJCR

I have corrected as you have mentioned and it worked and reporting warning level as per output.
Thanks for it.

Hope i should do the same for other threshold levels conditions too

Haven't we been here before??
https://www.linuxquestions.org/quest...ed-4175673188/

Almost the same problem, just with a different script. And again, we aren't on your 'team'...we are not your co-workers, but volunteers who try to help others. We're happy to do so, but you have to show that you're applying what you're getting told and taking the advice offered. Otherwise, we're just doing all your debugging work for you.

2 members found this post helpful.

Anyway, why not try running a program such as (for example) glances in a terminal screen.
It will monitor your swap and a host of other things...

1 members found this post helpful.

Putting alert thresholds on swap usage does not make much sense. Better monitor available RAM + swap.

1 members found this post helpful.

Regarding the reported problem, comparing strings can go wrong.
But you can compare pure numbers (without a percent sign)

1 members found this post helpful.

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.

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.