Shell Programming and Scripting

Hi
I have 10 directories.I want to delete all the dicrectories except the three recent directories based on timestamp.I am new to BASH can u help me?

EDIT - Code was simplified

Code:

#!/bin/bash

f1=$(mktemp)

for i in *; do
    if [ -d "$i" ]; then
        echo "$(stat -c %Y $i)"$'\t'"$i" >> "$f1"
    fi
done
sort -n "$f1" | head -n-3 | while read l; do
    echo "${l#*$'\t'}"
done

#rm "$f1" "$f2"

exit 0

It should do the trick.
Place this script in the directory you want dirs to be removed.
Explanations:
We create a temporay files: f1
For every file (i) in the folder, check if it's a directory (-d "$i").
If so, create an entry in the temp file (f1) (use stat --help to see what's going on there) ($'\t' is a TAB)
Once every file is processed, sort f1 so older entries are on the top of the file (see sort --help). Output is piped to head, that will display all but the 3 latest lines (the most recent entries), and redirected to the last loop that reads every line and echoes the actual filename. Replace the last echo command with rm -r once you are sure the script is OK.

(The #commented last rm command removes the temp files. Remove the # to actually execute this command)