Shell Programming and Scripting

ok, this one is definitely too hard for my shell-script-skills.
Hopefully, there is somebody who can help me with this:

I have a folder with files in it named

0.ppm
10.ppm
2.ppm
...
5.ppm
50.ppm
55.ppm
...
355.ppm
360.ppm
etc.

As you will notice, the order in which the files are processed is not
right, because it should be 5,10,15,20etc. However, because of the
shorter filenames for some of the files, they are sorted in a different
than the mathematical sense.

What I need right now is a script which runs through the data and
checks the filenames. If it is shorter than three, there have to be
zeroes added in front of the number such that I get

005.ppm
010.ppm
015.ppm
020.ppm

and thus a natural way of sorting..

It would be just perfect if anyone could point me in the right
direction.

Thanks so much!

If you have Python, here is an alternative:

Code:

#!/usr/bin/python
import glob
files = glob.glob("*.ppm")
for f in sorted(files):
	print f

output:

Code:

/home> python test.py
1.ppm
10.ppm
2.ppm
5.ppm
50.ppm

You could use sort -n to sort numerically, or to rename files try...

Code:

for i in *.ppm
do
  j=$(printf "%03d.%s" ${i%.*} ${i#*.})
  [[ $i != $j ]] && mv $i $j
done

I used

for file in *.ppm
do
case $file in
??.ppm) mv "$file" "0$file,ppm" ;;
?.ppm) mv "$file" "00$file,ppm" ;;
esac
done

which works seamlessly

Thanks for the suggestions

renaming directories works with

> for file in *
> do
> case $file in
> ??) mv "$file" "0$file" ;;
> ?) mv "$file" "00$file" ;;
> esac
> done

so please forget about this last post where I originally asked exactly this question

use following

#! /usr/bin/ksh

for fname in `ls *.ppm`
do
wcount=`echo $fname | wc -c`
echo $wcount
if [[ $wcount -eq 6 ]]
then
newfile=00$fname
mv $fname $newfile
fi

if [[ $wcount -eq 7 ]]
then
newfile=0$fname
mv $fname $newfile
fi
#echo $newname
done