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Use awk to compare values piped from df

Use awk to compare values piped from df

I want to use awk to compare values piped from "df" like so:


CODE -->

Filesystem     1K-blocks      Used Available Use% Mounted on
/dev/sda1      725649232 118249576 571080120  18% /
udev             2994044         4   2994040   1% /dev
tmpfs            1201132      1120   1200012   1% /run
none                5120         0      5120   0% /run/lock
none             3002824       352   3002472   1% /run/shm
/dev/sr0         5487686   5487686         0 100% /media/UDF Volume 

Then pull out the red values:


And run a comparison:

if 2994040 > 1200012 then:
echo "udev exceeds tmpfs in size"
else echo "udev is smaller than tmpfs in size"

Something like that. I've gotten this far:

CODE -->

 awk '{print $c}' c=${1:-2} 

I put the above into "colmn" and then ran:

df | ./column which outputs:



I don't know how to grab the values I want, and I don't want to use cut. I want it to be smart enough to read the lines that go with udev or tmpfs (or whatever lines I specify). I imagine that if I can grab the values then I can store them in variables somehow and then run some comparison logic, but I don't know how to put it all together.


RE: Use awk to compare values piped from df


CODE --> command-line

df | awk '$1=="udev"||$1=="tmpfs"{s[$1]+=$4}END{printf"udev %s tmpfs in size",(s["udev"]>s["tmpfs"])?"exceeds":"is smaller than"}' 
Tested with gawk and mawk.

Note that on my machine there are 7 tmpfs entries in df's output, so I put my code to add them and compare the sums.


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