diff --git a/backup.sh b/backup.sh
index 4f90970..4492db5 100644
--- a/backup.sh
+++ b/backup.sh
@@ -2,27 +2,30 @@
 [ -z "${MYSQL_USER}" ] && { echo "=> MYSQL_USER cannot be empty" && exit 1; }
 [ -z "${MYSQL_PASS}" ] && { echo "=> MYSQL_PASS cannot be empty" && exit 1; }
 
-DATE=`date +%Y%m%d%H%M`
+DATE=$(date +%Y%m%d%H%M)
 echo "=> Backup started at $DATE"
-databases=`mysql -u $MYSQL_USER -p$MYSQL_PASS -e "SHOW DATABASES;" | tr -d "| " | grep -v Database`
+databases=$(mysql -u "$MYSQL_USER" -p"$MYSQL_PASS" -e "SHOW DATABASES;" | tr -d "| " | grep -v Database)
 for db in $databases; do
-  if [[ "$db" != "information_schema" ]] && [[ "$db" != "performance_schema" ]] && [[ "$db" != "mysql" ]] && [[ "$db" != _* ]] ; then
+  if [[ "$db" != "information_schema" ]] && [[ "$db" != "performance_schema" ]] && [[ "$db" != "mysql" ]] && [[ "$db" != _* ]]
+  then
     echo "Dumping database: $db"
     FILENAME=/backup/$DATE.$db.sql
-    if mysqldump -h $MYSQL_HOST -P $MYSQL_PORT -u $MYSQL_USER -p$MYSQL_PASS $db > $FILENAME ;then
-      gzip -f $FILENAME
+    if mysqldump -h "$MYSQL_HOST" -P "$MYSQL_PORT" -u "$MYSQL_USER" -p"$MYSQL_PASS" "$db" > "$FILENAME"
+    then
+      gzip -f "$FILENAME"
     else
-      rm -rf $FILENAME
+      rm -rf "$FILENAME"
     fi
   fi
 done
 
-if [ -n "$MAX_BACKUPS" ]; then
-  while [ `ls -1 /backup | wc -l` -gt "$MAX_BACKUPS" ];
+if [ -n "$MAX_BACKUPS" ]
+then
+  while [ $(find /backup -maxdepth 1 -name "*.sql.gz" | wc -l) -gt "$MAX_BACKUPS" ];
   do
-    TARGET=`ls -1 /backup | sort | head -n 1`
-    echo "Backup ${TARGET} is deleted"
-    rm -rf /backup/${TARGET}
+    TARGET=$(find /backup -maxdepth 1 -name "*.sql.gz" | sort | head -n 1)
+    echo "Backup $TARGET is deleted"
+    rm -rf /backup/"$TARGET"
   done
 fi
 
diff --git a/restore.sh b/restore.sh
index d9dd5c4..de67315 100644
--- a/restore.sh
+++ b/restore.sh
@@ -1,6 +1,6 @@
 #!/bin/bash
-echo "=> Restore database from \$1"
-if mysql -h $MYSQL_HOST -P $MYSQL_POR -u $MYSQL_USER -p$MYSQL_PASS < \$1 ;then
+echo "=> Restore database from $1"
+if mysql -h "$MYSQL_HOST" -P "$MYSQL_PORT" -u "$MYSQL_USER" -p"$MYSQL_PASS" < "$1" ;then
     echo "=> Restore succeeded"
 else
     echo "=> Restore failed"
diff --git a/run.sh b/run.sh
index 1d3fefa..f821cd6 100755
--- a/run.sh
+++ b/run.sh
@@ -7,12 +7,12 @@ if [ -n "${INIT_BACKUP}" ]; then
   /backup.sh
 elif [ -n "${INIT_RESTORE_LATEST}" ]; then
   echo "=> Restore latest backup"
-  until nc -z $MYSQL_HOST $MYSQL_PORT
+  until nc -z "$MYSQL_HOST" "$MYSQL_PORT"
   do
       echo "waiting database container..."
       sleep 1
   done
-  ls -d -1 /backup/* | tail -1 | xargs /restore.sh
+find /backup -maxdepth 1 -name '*.sql.gz' | tail -1 | xargs /restore.sh
 fi
 
 echo "${CRON_TIME} /backup.sh >> /mysql_backup.log 2>&1" > /crontab.conf