removes oldest file in a given folder, if the filesystem only has 10 Gigs remaining.

delo.sh

#!/bin/sh

dir=$1
minGigs=$2
available=`df --sync $dir | grep -vE '^Filesystem|tmpfs|cdrom' | awk '{print $4}'`

#10 Gbytes in Kbytes
min=$(($minGigs*1024*1024))

if [ $min -gt $available ]
then

        file2rm=`ls --sort=time $dir | awk '{ fname=$1 } END { print fname }'`
        rm -rf $file2rm
        echo "$file2rm removed"
else
        echo "there's more than $minGigs Gigs"
fi