Need help writing a shell script/cron job

Here is my issue:

I have to write a shell script that archives pictures stored in a directory.

within my /home/pictures directory, jpegs get saved.

Once the folder gets large enough (100MB), I would like to make a tar.gz archive all the files located in the directory, and move them to /home/archives.

How would I go about writing a shell script/cron job to perform this?

 

here is what I have so far:

Code:

#!/bin/bash
# Backup Script

echo "\nWelcome to the backup script\n"
cd /home/images

if [$du -h /home/images] >= 100MB ; then
   tar -pczf `date`.tar.gz /home/pictures/backup
fi

exit 0;

This doesn't work right.

 

Try this

Code:

#!/bin/bash
# Backup Script

echo "\nWelcome to the backup script\n"
path="/home/images"

if [ `du -ms $path` > 1000 ] ; then
        find $path > /tmp/list.txt
        tar -T /tmp/list.txt -pczf `date`.tar.gz
        for i in `cat /tmp/list.txt`; do
                rm -rf $i
        done
fi

exit 0;