topic Re: How to compare 2 numbers from a string in Operating System - Linux

How to compare 2 numbers from a string

Carles Viaplana — Tue, 20 Sep 2005 12:15:02 GMT

Hello,

I need to check filesystem used and free space, so I want to get percentage and compare it with a value.

Script I'm using doesn't work fine in some cases due data I get from system is a string (ie, in case of percentage is 9, for my script it's greater than 85):

bdf -l|tail +2|awk 'substr($5,1,length($5)-1) > 85 && $6 == "/FAR/oracle/arch" {print}'

Is there any way to change format to an integer or to change ">" for any other command?

Thanks in advance,

Carles

Re: How to compare 2 numbers from a string

James R. Ferguson — Tue, 20 Sep 2005 12:25:41 GMT

Hi Carles:

You can force 'awk' to intergize by adding zero. Try this:

bdf -l|tail +2|awk '{n=substr($5,1);n=n+0;if (n > 85 && $6 == "/FAR/oracle/arch" {print}}'

Regards!

...JRF...

Re: How to compare 2 numbers from a string

James R. Ferguson — Tue, 20 Sep 2005 12:41:10 GMT

Hi (again):

Oops, I dropped the chop of the "%":

# bdf -l|tail +2|awk '{n=substr($5,1,(length($5)-1));n=n+0;if (n > 85 && $6 == "/FAR/oracle/arch" {print}}'

You could also eliminate the extra process (the 'tail':

# smhmso # bdf -l|awk '{NR>2;n=substr($5,1,($length($5)-1));n=n+0;if (n > 85 && $6 == "/FAR/oracle/arch" {print}}'

Regards!

...JRF...
Regards!

...JRF...

Re: How to compare 2 numbers from a string

Hein van den Heuvel — Tue, 20 Sep 2005 13:02:34 GMT

I would let awk do more work:

bdf -l| awk '/arch$/{sub(/%/,"",$5); if ((0+$5)>85){print}}'

Here tail is replaced by awk just lookinf for a line ending in 'arch'.
You can extent that to \/FAR\/oracle\/arch$ if need be.
It then replaces the % in $5 with nothing, converts to numeric and compares.

fwiw,
Hein.

Re: How to compare 2 numbers from a string

Sandman! — Tue, 20 Sep 2005 15:21:34 GMT

Is the output of bdf -l getting wrapped onto another line (happens when the name of the devices is long)???

If that's the case then your script will not be able to parse, compare and print the filesystems that are exceeding your "> 85" criteria. You need to modify your script as:

# bdf -l | awk 'NR!=1 && NF!=1 && substr($(NF-1),1,length($(NF-1))-1) > 85 && $6 == "/FAR/oracle/arch" {print}'

Re: How to compare 2 numbers from a string

Sandman! — Tue, 20 Sep 2005 15:24:31 GMT

Hello...small change to the previous posting; change the $6 with $NF i.e.

# bdf -l | awk 'NR!=1 && NF!=1 && substr($(NF-1),1,length($(NF-1))-1) > 85 && $NF == "/FAR/oracle/arch" {print}'

regards!

Re: How to compare 2 numbers from a string

Bill Hassell — Tue, 20 Sep 2005 15:48:17 GMT

As mentioned, bdf is unstable when it comes to the lines of data. If you use bdf directly, your script will fail with long device filenames or NFS mountpoints. It is a very common task so I've attached a useful diskspace monitoring script with configurable % per mountpoint *and* a notification only once per limit, with another notice when the usage increases a specified amount over the limit.

Re: How to compare 2 numbers from a string

Alan Meyer_4 — Tue, 20 Sep 2005 18:38:37 GMT

Here's a perl script I wrote to force bdf into 1 line per filesystem. The problem referenced in Bills post.

Re: How to compare 2 numbers from a string

Carles Viaplana — Wed, 21 Sep 2005 01:59:04 GMT

I applied solution provided by James and it works fine.

Thanks to all!