UNIX for Dummies Questions & Answers

Hi all,

I have a requirement for a script to find out the increase in memory. We have a log native_stderr.log where this will log.

bash-2.05$ tail -40 native_stderr.log | grep ': freed'
<GC(4140): freed 168190456 bytes, 66% free (180990488/271776256), in 253 ms>
<GC(4141): freed 167436384 bytes, 66% free (180290224/271776256), in 414 ms>
<GC(4142): freed 168588096 bytes, 66% free (181440728/271776256), in 352 ms>

Here i have put some more filter and able to get the values.

tail -40 native_stderr.log | grep ': freed' | awk -F '(' '{print $3}' | awk -F '/|)' '{print $1, $2}'
178893640 271776256
178153688 271776256
178595056 271776256

but i need to find out the differnce between the last line $1 value and the second last line value $1

like 178595056 - 178153688 = 441368 bytes
then change to MB 441368/(1024*1024) = 0.42

if this value is more than 50 MB then i need to send mail. Could you please some one help on this.

Thanks
Senthilkumar AK


-----Post Update-----

i have found some way but still your expert views needed on this

tail -40 native_stderr.log | grep ': freed' | awk -F '(' '{print $3}' | awk -F '/|)' '{a=($2-$1)/(1024*1024);y=x "\n" a; x=a};END{printf "%-15s%3.2f%-2s\n", "Difference is", x-y, " MB"}'

Thanks
Senthyilkumar

Assuming the lines of interest are of the same format ( as posted ) and they're always present in the last 40 records of the log file, you can do something like this:

Code:

tail -40 logfile | awk -F'[(/)]' '/: freed/{ y=x; x=$4 }END{ print (x-y)/(1024*1024) " MB"}'

Something along the lines of ...

Code:

[ $(tail -40 logfile | awk -F'[(/)]' '/: freed/{ y=x; x=$4 }END{ print int((x-y)/(1024*1024)) }') -gt 50 ] && \
                                       mail -s "Attention" user@mail.com || echo OK

#the test expects integers only, ( bash )!

or calling the mail command with the system function in the END statement:

Code:

tail ... | awk '{...} END{ if((d=(x-y)/(1024*1024))>n) system("mail -s "Attention" user@mail.com"); else print d " MB" }' n=50

Modify it to your needs.

Thanks very much rubin

but one query i have

bash-2.05$ tail -40 native_stderr.log | grep ': freed' | awk -F '(' '{print $3}' | awk -F '/|)' '{a=($2-$1)/(1024*1024);y=x "\n" a; x=a};END{printf "%-15s%3.2f%-2s\n", "Difference is", x-y, " MB"}'
Difference is 0.40 MB
bash-2.05$ tail -40 native_stderr.log | awk -F'[(/)]' '/: freed/{ y=x; x=$4 }END{ print (x-y)/(1024*1024) " MB"}'
-0.398109 MB

Your query give the result in negative.

Do we missed anything.
Thanks
Senthil kumar ak.

Code:

tail -3 file  | awk '{ p=last ; last=$1}END{  print $1-p}'

As per my understanding of your requirement, the code works as expected.


I see that you need to substract the second to the last line value ( in blue ) from the last line value ( in red ), disregarding entirely all the previous records, ( as I see it ).
My conclusions stemmed from your posted code, which points to those colored values ( btw there's a missmatch between your first and second tail in your first post, I used the first ). In absence of a good sample, I provided my own:

( Displaying only the last records )

Code:

$ tail logfile
....
<GC(4140): freed 168190456 bytes, 66% free (180990488/271776256), in 253 ms>
data other data other data
data other data other data
<GC(4141): freed 167436384 bytes, 66% free (180290224/271776256), in 414 ms>
data other data other data
<GC(4142): freed 168588096 bytes, 66% free (181440728/271776256), in 352 ms>
data other data other data


$ tail -40 logfile | awk -F'[(/)]' '/: freed/{ y=x; x=$4 }END{ print  "x->" x " y->" y " |difference in MB-> " (x-y)/(1024*1024) }'

x->181440728 y->180290224 |difference in MB-> 1.09721

I believe the main issue of extracting the last adjacent values is resolved, so little effort is needed modifying the code.