AWK Print Second Column of Last Line

Question

I'm trying to use AWK to post the second row of last line of this command (the total disk space):

df --total

The command I'm using is:

df --total | awk 'FNR == NF {print $2}'

But it does not get it right. Is there another way to do it?

Answer 1

You're using the awk variable NF which is Number of Fields. You might have meant NR, Number of Rows, but it's easier to just use END:

df --total | awk 'END {print $2}'

Answer 2

You can use tail first then use awk:

df --total | tail -1 | awk '{print $2}'

Answer 3

One way to do it is with a tail/awk combination, the former to get just the last line, the latter print the second column:

df --total | tail -1l | awk '{print $2}'

A pure-awk solution is to simply store the second column of every line and print it out at the end:

df --total | awk '{store = $2} END {print store}'

Or, since the final columns are maintained in the END block from the last line, simply:

df --total | awk 'END {print $2}'