diff --git a/data/hooks/backup/05-conf_ldap b/data/hooks/backup/05-conf_ldap
index b6f6a5f1c..b21103ede 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 36b8d4025..ae422617e 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 81e22d851..60bd8c017 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 6c31bb80b..ca42d3369 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 07f190e99..9e5aba5a5 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 813d0cd2a..4e08114e7 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 3f4cbcfdf..f9687164d 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 405a2726f..618a0aafe 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 38806f284..12300a00a 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 3f8f3a43f..d900c7535 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 e48cbc6ab..2fea9f53f 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 d7579b908..e4a684576 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"