diff --git a/data/hooks/backup/05-conf_ldap b/data/hooks/backup/05-conf_ldap
index b6f6a5f1..b21103ed 100755
--- a/data/hooks/backup/05-conf_ldap
+++ b/data/hooks/backup/05-conf_ldap
@@ -4,7 +4,7 @@
 set -eu
 
 # Source YNH helpers
-. /usr/share/yunohost/helpers.d/filesystem
+source /usr/share/yunohost/helpers.d/filesystem
 
 # Backup destination
 backup_dir="${1}/conf/ldap"
diff --git a/data/hooks/backup/08-conf_ssh b/data/hooks/backup/08-conf_ssh
index 36b8d402..ae422617 100755
--- a/data/hooks/backup/08-conf_ssh
+++ b/data/hooks/backup/08-conf_ssh
@@ -4,7 +4,7 @@
 set -eu
 
 # Source YNH helpers
-. /usr/share/yunohost/helpers.d/filesystem
+source /usr/share/yunohost/helpers.d/filesystem
 
 # Backup destination
 backup_dir="${1}/conf/ssh"
diff --git a/data/hooks/backup/11-conf_ynh_mysql b/data/hooks/backup/11-conf_ynh_mysql
index 81e22d85..60bd8c01 100755
--- a/data/hooks/backup/11-conf_ynh_mysql
+++ b/data/hooks/backup/11-conf_ynh_mysql
@@ -4,7 +4,7 @@
 set -eu
 
 # Source YNH helpers
-. /usr/share/yunohost/helpers.d/filesystem
+source /usr/share/yunohost/helpers.d/filesystem
 
 # Backup destination
 backup_dir="${1}/conf/ynh/mysql"
diff --git a/data/hooks/backup/14-conf_ssowat b/data/hooks/backup/14-conf_ssowat
index 6c31bb80..ca42d336 100755
--- a/data/hooks/backup/14-conf_ssowat
+++ b/data/hooks/backup/14-conf_ssowat
@@ -4,7 +4,7 @@
 set -eu
 
 # Source YNH helpers
-. /usr/share/yunohost/helpers.d/filesystem
+source /usr/share/yunohost/helpers.d/filesystem
 
 # Backup destination
 backup_dir="${1}/conf/ssowat"
diff --git a/data/hooks/backup/17-data_home b/data/hooks/backup/17-data_home
index 07f190e9..9e5aba5a 100755
--- a/data/hooks/backup/17-data_home
+++ b/data/hooks/backup/17-data_home
@@ -4,7 +4,7 @@
 set -eu
 
 # Source YNH helpers
-. /usr/share/yunohost/helpers.d/filesystem
+source /usr/share/yunohost/helpers.d/filesystem
 
 # Backup destination
 backup_dir="${1}/data/home"
diff --git a/data/hooks/backup/20-conf_ynh_firewall b/data/hooks/backup/20-conf_ynh_firewall
index 813d0cd2..4e08114e 100755
--- a/data/hooks/backup/20-conf_ynh_firewall
+++ b/data/hooks/backup/20-conf_ynh_firewall
@@ -4,7 +4,7 @@
 set -eu
 
 # Source YNH helpers
-. /usr/share/yunohost/helpers.d/filesystem
+source /usr/share/yunohost/helpers.d/filesystem
 
 # Backup destination
 backup_dir="${1}/conf/ynh/firewall"
diff --git a/data/hooks/backup/21-conf_ynh_certs b/data/hooks/backup/21-conf_ynh_certs
index 3f4cbcfd..f9687164 100755
--- a/data/hooks/backup/21-conf_ynh_certs
+++ b/data/hooks/backup/21-conf_ynh_certs
@@ -4,7 +4,7 @@
 set -eu
 
 # Source YNH helpers
-. /usr/share/yunohost/helpers.d/filesystem
+source /usr/share/yunohost/helpers.d/filesystem
 
 # Backup destination
 backup_dir="${1}/conf/ynh/certs"
diff --git a/data/hooks/backup/23-data_mail b/data/hooks/backup/23-data_mail
index 405a2726..618a0aaf 100755
--- a/data/hooks/backup/23-data_mail
+++ b/data/hooks/backup/23-data_mail
@@ -4,7 +4,7 @@
 set -eu
 
 # Source YNH helpers
-. /usr/share/yunohost/helpers.d/filesystem
+source /usr/share/yunohost/helpers.d/filesystem
 
 # Backup destination
 backup_dir="${1}/data/mail"
diff --git a/data/hooks/backup/26-conf_xmpp b/data/hooks/backup/26-conf_xmpp
index 38806f28..12300a00 100755
--- a/data/hooks/backup/26-conf_xmpp
+++ b/data/hooks/backup/26-conf_xmpp
@@ -4,7 +4,7 @@
 set -eu
 
 # Source YNH helpers
-. /usr/share/yunohost/helpers.d/filesystem
+source /usr/share/yunohost/helpers.d/filesystem
 
 # Backup destination
 backup_dir="${1}/conf/xmpp"
diff --git a/data/hooks/backup/29-conf_nginx b/data/hooks/backup/29-conf_nginx
index 3f8f3a43..d900c753 100755
--- a/data/hooks/backup/29-conf_nginx
+++ b/data/hooks/backup/29-conf_nginx
@@ -4,7 +4,7 @@
 set -eu
 
 # Source YNH helpers
-. /usr/share/yunohost/helpers.d/filesystem
+source /usr/share/yunohost/helpers.d/filesystem
 
 # Backup destination
 backup_dir="${1}/conf/nginx"
diff --git a/data/hooks/backup/32-conf_cron b/data/hooks/backup/32-conf_cron
index e48cbc6a..2fea9f53 100755
--- a/data/hooks/backup/32-conf_cron
+++ b/data/hooks/backup/32-conf_cron
@@ -4,7 +4,7 @@
 set -eu
 
 # Source YNH helpers
-. /usr/share/yunohost/helpers.d/filesystem
+source /usr/share/yunohost/helpers.d/filesystem
 
 # Backup destination
 backup_dir="${1}/conf/cron"
diff --git a/data/hooks/backup/40-conf_ynh_currenthost b/data/hooks/backup/40-conf_ynh_currenthost
index d7579b90..e4a68457 100755
--- a/data/hooks/backup/40-conf_ynh_currenthost
+++ b/data/hooks/backup/40-conf_ynh_currenthost
@@ -4,7 +4,7 @@
 set -eu
 
 # Source YNH helpers
-. /usr/share/yunohost/helpers.d/filesystem
+source /usr/share/yunohost/helpers.d/filesystem
 
 # Backup destination
 backup_dir="${1}/conf/ynh"