Shell script to backup all specified directories using cron job

daily_backup.sh

#!/usr/bin/env bash
# Author:   M. Dutt ([email protected])
# Date:     28/10/2023
# Purpose:  Backup all specified direcories.
# License:  This shell script is released under GPL v2.
#

########################
# REQUIREMENTS
########################
#
#   * Required commands:
#       + du
#       + tar     
#

########################
# USAGE
########################
#
#   * It stores all backup copies in directory '/var/backup' by default,
#     You can change it in variable $BACKUP_DIR below.
#
#   * Add crontab job for root user:
#
#       # crontab -e -u root
#       10   0   *   *   *   /bin/bash /var/daily_backup.sh
#

KEEP_DAYS='7'
export BACKUP_DIR="/var/backup"
export DIRECTORIES='directory1 directory2 directory3 directory4'

export CMD_DATE='/bin/date'
export CMD_DU='du -sh'
export YEAR="$(${CMD_DATE} +%Y)"
export MONTH="$(${CMD_DATE} +%m)"
export DAY="$(${CMD_DATE} +%d)"
export TIME="$(${CMD_DATE} +%H-%M-%S)"
export TIMESTAMP="${YEAR}-${MONTH}-${DAY}-${TIME}"
export BACKUP_SUCCESS='YES'
export PATH='/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/usr/local/sbin'

export LOGFILE="${BACKUP_DIR}/${TIMESTAMP}.log"

[ ! -d ${BACKUP_DIR} ] && mkdir -p ${BACKUP_DIR} 2>/dev/null
chown root ${BACKUP_DIR}
chmod 0400 ${BACKUP_DIR}

echo "* Starting backup: ${TIMESTAMP}." >${LOGFILE}
echo "* Backup directory: ${BACKUP_DIR}." >>${LOGFILE}
chmod 0400 ${LOGFILE}

echo "* Backing up directories: ${DIRECTORIES}." >> ${LOGFILE}
for d in ${DIRECTORIES}; do
        tar --exclude='vendor' --exclude='.git' --exclude='node_modules' --exclude='wp-admin' --exclude='wp-includes' -cjf ${BACKUP_DIR}/${d}-${TIMESTAMP}.tar.bz2 -C /var/www ${d} >>${LOGFILE}
        compressed_size="$(${CMD_DU} ${BACKUP_DIR}/${d}-${TIMESTAMP}.tar.bz2 | awk '{print $1}')"
	if [ X"$?" == X'0' ]; then
		sleep 10
	else
		export BACKUP_SUCCESS='NO'
	fi
done

echo -e "* File size:\n----">>${LOGFILE}
cd ${BACKUP_DIR} && \
${CMD_DU} *${TIMESTAMP}* >>${LOGFILE}
echo "----" >>${LOGFILE}

echo "* Backup completed (Success? ${BACKUP_SUCCESS})." >>${LOGFILE}

if [ X"${BACKUP_SUCCESS}" == X'YES' ]; then
    echo "==> Backup completed successfully."
else
    echo -e "==> Backup completed with !!!ERRORS!!!.\n" 1>&2
fi

find ${BACKUP_DIR}/* -type f -mtime +${KEEP_DAYS} -print | while read -r file; do
    echo "* Old backup found. Deleting: ${file}." >>${LOGFILE}
    rm "$file"
done
	
echo "==> Detailed log (${LOGFILE}):"
echo "=============================="
cat ${LOGFILE}