diff --git a/keyserver/bash/backup-phabricator.sh b/keyserver/bash/backup-phabricator.sh
--- a/keyserver/bash/backup-phabricator.sh
+++ b/keyserver/bash/backup-phabricator.sh
@@ -10,13 +10,13 @@
 BACKUP_PATH=/mnt/backup
 
 # The user that will be owning the backup files
-BACKUP_USER=comm
+BACKUP_USER="comm"
 
 # The maximum amount of space to spend on Phabricator backups
 MAX_DISK_USAGE_KB=204800 # 200 MiB
 
 set -e
-[[ `whoami` = root ]] || exec sudo su -c "$0"
+[[ $(whoami) = root ]] || exec sudo su -c "$0"
 
 cd "$PHABRICATOR_PATH"
 
@@ -42,14 +42,14 @@
   ((RETRIES--))
 done
 
-chown $BACKUP_USER:$(id -gn $BACKUP_USER) "$OUTPUT_FILE" || true
+chown $BACKUP_USER:"$(id -gn $BACKUP_USER)" "$OUTPUT_FILE" || true
 
 while true; do
-  TOTAL_USAGE=$(sudo du -cs "$BACKUP_PATH"/phabricator.*.sql.gz | grep total | awk '{ print $1 }')
+  TOTAL_USAGE=$(sudo du -cs "$BACKUP_PATH"/phabricator.*.sql.gz | awk '/total/ { print $1 }')
   if [[ $TOTAL_USAGE -le $MAX_DISK_USAGE_KB ]]; then
     break
   fi
-  BACKUP_COUNT=$(ls -hla "$BACKUP_PATH"/phabricator.*.sql.gz | wc -l)
+  BACKUP_COUNT=$(find "$BACKUP_PATH" -maxdepth 1 -name 'phabricator.*.sql.gz' -type f | wc -l)
   if [[ $BACKUP_COUNT -lt 2 ]]; then
     break
   fi