#!/bin/sh
########## Renum all files in a directory ################
# Rename/Renum all files within a directory
# Please provide a directory and an extension (example: jpg)
# Be VERY careful not to override file names
# If files already have .jpg extension, rename to jpg1 
##########################################################
 
if [ $# -lt 2 ]
then
    echo "Please provide 1) Name of directory, and 2) Extension type. Example: jgp"
    exit 1
fi

dir=$1
ext=$2
num=0

cd $dir

/bin/ls -1 |                          #ls (filenames only) 1 per line
 
while read name                       #while there are names
do
    if [ $name -a $name != r ]        #if the name is not empty and not r
    then
        num=$((num + 1))                       #add 1 to num
        newname=$num.$ext                      #create the new name
        if [ $num -lt 10 ]                     #if num < 10
            then newname=0$newname             #append leading 0
        fi
        if [ $num -lt 100 ]                    #if num < 100
            then newname=0$newname             #append leading 0
        fi
        echo "renaming $name -> $newname"
        mv $name $newname                      #rename the file
    fi
done