This bash script takes two command line arguments which is the name of the directory and number of files to keep. It will count the number of files and delete any extra. Ideal for tracking and deleting extra backup files made automatically in a directory

file_count.sh

#!/bin/sh
# this script takes two command line arguments which is the name of the directory to count files in and number of files to keep in directory
# must use full path to directory (i.e. /home/path_to_directory) as first argument
# the script counts the number of files in the directory and if more than number to keep, extra files will be deleted
# it will delete the oldest database files over the number to keep
# ideal for deleting old copies of backup files.
dir="$1"
num_to_keep="$2"
cd $dir
shopt -s nullglob
numfiles=(*)
numfiles=${#numfiles[@]}
echo "Number of files is $numfiles"
unset -v oldest
if [[ $numfiles -gt $num_to_keep ]]
then
        echo "$numfiles is greater than $num_to_keep"
        while [[ $numfiles -gt $num_to_keep ]]
        do
                for file in "$dir"/*; do
                        [[ -z $oldest || $file -ot $oldest ]] && oldest=$file
                done
                echo "The oldest file in the directory is $oldest"
                if [[ $oldest == *".sql" ]]
                then
                        echo "The oldest file is an sql database file"
                        rm $oldest
                        unset -v oldest
                        let "numfiles=$numfiles - 1"
                        echo "Number of files is now $numfiles"
                else
                        echo "The oldest file is not a database file"
                        let "numfiles=$numfiles"
                        touch $oldest
                fi
        done
else
        echo "$numfiles is equal to or less than $num_to_keep"
fi