df -k

Filesystem            kbytes    used   avail capacity  Mounted on
/dev/vx/dsk/rootvol  4131866 3593302  497246    88%    /
/proc                      0       0       0     0%    /proc
fd                         0       0       0     0%    /dev/fd
mnttab                     0       0       0     0%    /etc/mnttab
swap                 19891520     144 19891376     1%    /var/run
swap                 19913552   22176 19891376     1%    /tmp
/dev/vx/dsk/u01      112302757 30833295 80346435    28%    /u01
/dev/vx/dsk/node@1     96975    4977   82301     6%    /global/.devices/node@1
/dev/vx/dsk/node@2     96975    4988   82290     6%    /global/.devices/node@2
/dev/vx/dsk/stkdg/s03
                     1047527424 60483821 925353439     7%    /s03
/dev/vx/dsk/stkdg/s02
                     1048576000 266754165 732957997    27%    /s02
/dev/vx/dsk/sandg/s01
                     355923968 322572197 31422792    92%    /global/s01

df -k | grep / | awk '{ print $5}' | sort -r

92%
88%
7%
6%
6%
28%
27%
1%
1%
0%
0%
0%

92%
88%
28%
27%
 7%
 6%
 6%
 1%
 1%
 0%
 0%
 0%

:> df -k | grep / | awk '{print $5}' | sort -gr
100%
7%
2%
0%
0%

df -k | awk '/[/]/ { print $5}' | sort -rn

df -k | grep / | awk '{print $5}' | sort -gr
sort: illegal option -- g
usage: sort [-cmu] [-o output] [-T directory] [-S mem] [-z recsz]
        [-dfiMnr] [-b] [-t char] [-k keydef] [+pos1 [-pos2]] files...

df -k | 
  while read fs kb us av ca mo; do 
    case $ca in 
      *[0-9]% ) printf "%s\n" "$ca";;
    esac
done | sort -rn