rounding up in awk/shell

[Stefan Farrelly]

Hi all,

our usual memory.sh script which uses adb and the kernel to display the system memory total works fine on 10.20 and 11.0 but on 11.11 it computes to an integer instead of a round number, eg;

echo "phys_mem_pages/D" | adb /stand/vmunix /dev/kmem|grep phys|tail -1|awk '{printf $2/256}'

On our server with 768Mb of RAM shows 767.992

My question is how can we round this up in awk (should display 768) or using prinf. Ive tried but cant figure it. I know this can be done the long way in a shell script or probably in perl, definitely in C using round, but Im after a 1 liner using awk and/or printf to do it - and so that it works on servers with different memory sizes.

Thanks,

Stefan

[Jean-Luc Oudart]

Hi

echo "767.99" | awk '{printf("%d\n",$1 + 0.5);}'
768
echo "767.49" | awk '{printf("%d\n",$1 + 0.5);}'
767
echo "767.51" | awk '{printf("%d\n",$1 + 0.5);}'
768

Jean-Luc

[Dietmar Konermann]

What about

echo "phys_mem_pages/D" | adb /stand/vmunix /dev/kmem|tail -1|awk '{printf "%d",$2/256+.5}'

BTW, I dropped the grep... it failed on my 11.11 box.

Regards...
Dietmar.

[Stefan Farrelly]

Hey, come on guys, no simply adding 1 or .5 or whatever to it. I want to round up. Must be able to round with awk, or nawk, or bc or dc or bs ??? anyone ?

[Dietmar Konermann]

Hmmm, Stefan.

What's the differnence between rounding up X and rounding down (X+.5)? Why should a designer include such a redundant functionality? :)

Regards...
Dietmar.

[H.Merijn Brand (procura · Accepted solution]

why awk?

# echo 767.992 | perl -ne'printf"%.0f\n",$_'
768
#

[Stefan Farrelly]

sorry, im purely being pedandtic. I want to round up or down using awk or a shell script in a one liner if possible. You can do in C, probably in perl, but not in a simple shell script/command ?

[Stefan Farrelly]

Hi Procura,

That did it! you dont need perl - your printf function is rounding perfectly (>.5 = up, < .5 round down). This now works;

echo "phys_mem_pages/D" | adb /stand/vmunix /dev/kmem|grep phys|tail -1|awk '{printf "%.0f MB\n",$2/256}'

Thanks!

Stefan

[Jean-Luc Oudart]

As far as I knwo round does not exist (in awk)
Well , I build it
You may like it or Not, just try to help

echo $1 | awk '
function round(aa) {
return int( aa + 0.5 )
}
{
printf("%d\n",round($1));
}'

Jean-Luc

[Pete Randall]

Stefan,

Thankyou for asking. I've just been accepting the answer as is and rounding up myself. This is much better.

Eternally grateful,
Pete

[Tom Danzig]

To round up using awk:
echo "767.992" | awk '{printf("%5.0f\n",$0)}'

To round down using awk:
echo "767.992" | awk '{printf("%d\n",$0)}'

[Tom Danzig]

To be more specific in my previous post, Using %5.0f actually will properly round the number up or down as expected. Using %d simply truncates off the decimals printing only the integer portion.

[Stephen Serbe]

Isn't the forum great...
I had the same question and found my answer(s) right here using search. Thanks, Stephen

[Pete Randall]

Psssst - Stephen!!! That's Stefan!

;^)

Pete