regex help on unix df

Question

I need some help tweaking my code to look for another attribute in this unix df output:

Ex.

Filesystem     Size    Used   Avail Capacity         


        

Answer 1

Lots of variations on a theme here. I would keep the first line, since it gives a nice header:

$ perl -E '$,=" "; open my $fh, "-|", "df -k /tmp"; 
  while(<$fh>) { @a=split; say @a[3,4]}'

On second thought, this is a lot cleaner:

$ df -k /tmp | perl -naE '$,="\t"; say @F[3,4]'
Available       Capacity
20862392        92%

Final thought: don't use perl at all:

$ df -h /tmp | tr -s ' ' '\t'  | cut  -f 3,4

or

$ df -h /tmp | awk '{print $3 "\t" $4}'