nmap -iR 20 -sL -n|awk '{print $2}'|grep '^[0-9]'|uniq

You can use the 'uniq' command to handle duplicate lines in a file:

$ cat tst
a
a
b
c
c
d

$ uniq -d tst        //show duplicated lines
a
c

$ uniq -u tst        //show unique lines
b
d

$ uniq tst           //remove duplicates
a
b
c
d

You might want to get rid of the awk, sort, uniq and grep depending on how much info you need.

for dir in $(find /proc -maxdepth 1 -type d -name "*[0-9]");do ls -l $dir/fd/ | awk '{print $11}';done | sort | uniq | grep "^/var/"