Linux – Cleaner Way to Delete Files with Datestamp in Name

I have a new requirement to purge MySQL dump files that are older than 30 days. The files use a naming convention of "all-mysql-YYYYMMDD-HHMM.dump". The files are located on SAN mounted file system, so restoration is not an issue, but the drive space is limited unfortunately and fills up quickly so it requires frequent human intervention.

Example of files names

• all-mysql-20130324-2330.dump
• all-mysql-20130325-2330.dump
• all-mysql-20130326-2330.dump

My first thought was to use "find" inside a batch script with -mtime +30, however, the modification times cannot be guaranteed and some of the older archives could evade the purge date 🙂

I created the following BASH script, but I was hoping there was there was a cleaner way to perform this operation.

#!/bin/bash

STARTING_DIR=$(pwd)

FILE_PREFIX=all-mysql-
BACKUP_DIR=/opt/backup/mysql/dumps
ARCHIVE_WINDOW_DAYS=30

cd $BACKUP_DIR

# Create YYYYMMDD datestamp for Today - $ARCHIVE_WINDOW_DAYS
ARCHIVE_WINDOW_IN_SECS=$(echo "$(date +%s) - (${ARCHIVE_WINDOW_DAYS} * 86400)" | bc)
PURGE_BEFORE_DATE=$(date -d @${ARCHIVE_WINDOW_IN_SECS} +%Y%m%d)

for backup_file in $FILE_PREFIX*
do
    # Trim prefix, time portion of date stamp, and file extension
    # from $backup_file to allow numeric comparison against YYYYMMDD
    backup_trim_tmp=${backup_file#${FILE_PREFIX}}
    backup_trimmed=${backup_trim_tmp%-****.dump}

    if [ ${PURGE_BEFORE_DATE} -gt ${backup_trimmed} ]
    then
        rm $backup_file
    fi
done

cd $STARTING_DIR