Simple backup script with rsync

#!/bin/bash
# ----------------------------------------------------------------------
# mikes handy rotating-filesystem-snapshot utility
# with heavy modifications by orl
# ----------------------------------------------------------------------
# this needs to be a lot more general, but the basic idea is it makes
# rotating backup-snapshots of $bak whenever called
# ----------------------------------------------------------------------
set -x
set -e
 
unset PATH      # suggestion from H. Milz: avoid accidental use of $PATH
 
# ------------- file locations -----------------------------------------
 
bak=/bak;
src=/srv/media;
excludes=/etc/opt/backup-exclude.txt;
 
# ------------- the script itself --------------------------------------
 
# make sure we are running as bak
if [[ $(/bin/whoami) != 'bak' ]]; then { echo "Sorry, must be 'bak'. Exiting..."; exit; } fi;
 
# make sure we didn't do snapshot today already
if [[ $(/bin/stat /bak/daily.0 | /bin/grep Modify | /bin/cut -d' ' -f2) == $(/bin/date '+%Y-%m-%d') && $1 != "--force" ]] ; then
        exit 2;
fi;
 
# ------------- make mysql backup --------------------------------------
 
mysql_pw='passwd';
date_suffix=$(/bin/date '+%Y-%m-%d');
/bin/mysqldump -uroot -p'passwd' zabbix | /bin/gzip -c > /bak/mysql/zabbix-$date_suffix.sql.gz;
unset mysql_pw;
 
openssl_pw='some-large-passphrase';
/bin/openssl aes-256-cbc -in /bak/mysql/zabbix-${date_suffix}.sql.gz -out /bak/mysql/zabbix-${date_suffix}.sql.gz.enc -pass pass:openssl_pw;
unset openssl_pw;
 
/bin/rm /bak/mysql/zabbix-$date_suffix.sql.gz;
 
total=$(/bin/find /bak/mysql -name 'zabbix*' | /bin/wc -l);
old=$(/bin/find /bak/mysql -name 'zabbix*' -mtime +30 | /bin/wc -l);
if (( total - old >= 30 )); then
        /bin/find /bak/mysql -name 'zabbix*' -mtime +30 -delete;
fi;
 
# ------------- rotating snapshots -------------------------------------
 
# step 1: delete the oldest snapshot, if it exists:
if [ -d $bak/daily.9 ] ; then
        /bin/rm -rf $bak/daily.9 ;
fi;
 
# step 2: shift the middle snapshots(s) back by one, if they exist
# cp /bin/mv $bak/daily.8 $bak/daily.9 ;
# cp /bin/mv $bak/daily.7 $bak/daily.8 ; # etc
for ((i=8;i>=1;i--)) ; do
        if [ -d $bak/daily.$i ] ; then
                /bin/mv $bak/daily.$i $bak/daily.$((i+1)) ;
        fi;
done;
 
# step 3: make a hard-link-only (except for dirs) copy of the latest snapshot,
# if that exists
if [ -d $bak/daily.0 ] ; then
        /bin/cp -al $bak/daily.0 $bak/daily.1 ;
fi;
 
# step 4: rsync from the system into the latest snapshot (notice that
# rsync behaves like cp --remove-destination by default, so the destination
# is unlinked first.  If it were not so, this would copy over the other
# snapshot(s) too!
/bin/rsync -va --delete --delete-excluded --exclude-from="$excludes" $src/ $bak/daily.0 |& >/dev/null ;
 
# step 5: update the mtime of daily.0 to reflect the snapshot time
/bin/touch $bak/daily.0 ;
 
# step 6: send backups to a backup server
/bin/lftp -c "set net:reconnect-interval-base 0; set ftp:ssl-force true; \
             open -u user,password ftp://backup-site.com:21; \
             mirror --verbose=3 -e -R -L -P 0 /bak/ /bak"