How to compare 2 numbers from a string

[Carles Viaplana]

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

[James R. Ferguson · Accepted solution]

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...

[James R. Ferguson]

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...

[Hein van den Heuvel]

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.

[Sandman!]

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}'

[Sandman!]

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!

[Bill Hassell]

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.

[Alan Meyer_4]

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

[Carles Viaplana]

I applied solution provided by James and it works fine.

Thanks to all!