#!/usr/bin/env bash

# @(#) s1	Demonstrate cp making "backup" copies of file that exist.

# Utility functions: print-as-echo, print-line-with-visual-space, debug.
# export PATH="/usr/local/bin:/usr/bin:/bin"
pe() { for _i;do printf "%s" "$_i";done; printf "\n"; }
pl() { pe;pe "-----" ;pe "$*"; }
db() { ( printf " db, ";for _i;do printf "%s" "$_i";done;printf "\n" ) >&2 ; }
db() { : ; }
C=$HOME/bin/context && [ -f $C ] && $C cp

FILE=data
N=${1-3}

pl " Input data file $FILE, making $N copies:"
cat $FILE

rm -rf d1
mkdir d1
pl " Initial content of directory d1:"
ls d1

pl " Content after making $N copies:"
for i in $( seq 1 $N )
do
  pe " Making copy $i"
  cp --backup=numbered $FILE d1
done
ls d1

exit 0

% ./s1

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
cp (GNU coreutils) 6.10

-----
 Input data file data, making 3 copies:
Now is the time.

-----
 Initial content of directory d1:

-----
 Content after making 3 copies:
 Making copy 1
 Making copy 2
 Making copy 3
data  data.~1~	data.~2~