Emergency UNIX and Linux Support

ls | awk -F. 'NF==1{NF++}{print $NF,$0}' OFS=. | sort -t. -k1,1 | cut -d. -f2-

#!/usr/bin/env bash

# @(#) user3	Demonstrate collect by extension.

pe() { for _i;do printf "%s" "$_i";done; printf "\n"; }
pl() { pe;pe "-----" ;pe "$*"; }
db() { ( printf " db, ";for _i;do printf "%s" "$_i";done;printf "\n" ) >&2 ; }
db() { : ; }
re() { perl -wn -e 'chomp;print scalar reverse,"\n";' $1 ; }
C=$HOME/bin/context && [ -f $C ] && $C msort perl sort

FILE=${1-data1}
pl " Input file $FILE:"
head $FILE

pl " Results for awk / sort / cut:"
awk -F. 'NF==1{NF++}{print $NF,$0}' OFS=. $FILE | sort -t. -k1,1 | cut -d. -f2-

exit 0

% ./user3 data3

Environment: LC_ALL = C, LANG = C
(Versions displayed with local utility "version")
OS, ker|rel, machine: Linux, 2.6.26-2-amd64, x86_64
Distribution        : Debian GNU/Linux 5.0.8 (lenny) 
bash GNU bash 3.2.39
msort 8.44
perl 5.10.0
sort (GNU coreutils) 6.10

-----
 Input file data3:
bar
foo
bar.zip
foo.zip
foo.bar.jpg
foo.bar.zip
bar.foo.zip
baz.

-----
 Results for awk / sort / cut:
bar.
baz.
foo.
foo.bar.jpg
bar.foo.zip
bar.zip
foo.bar.zip
foo.zip