diff --git a/data/helpers.d/filesystem b/data/helpers.d/filesystem
index 0d13c4825..f0f3afb06 100644
--- a/data/helpers.d/filesystem
+++ b/data/helpers.d/filesystem
@@ -81,6 +81,44 @@ properly with chmod/chown." >&2
     echo $TMP_DIR
 }
 
+# Calculate and store a file checksum into the app settings
+#
+# $app should be defined when calling this helper
+#
+# usage: ynh_store_file_checksum file
+# | arg: file - The file on which the checksum will performed, then stored.
+ynh_store_file_checksum () {
+	local checksum_setting_name=checksum_${1//[\/ ]/_}	# Replace all '/' and ' ' by '_'
+	ynh_app_setting_set $app $checksum_setting_name $(sudo md5sum "$1" | cut -d' ' -f1)
+}
+
+# Verify the checksum and backup the file if it's different
+# This helper is primarily meant to allow to easily backup personalised/manually 
+# modified config files.
+#
+# $app should be defined when calling this helper
+#
+# usage: ynh_backup_if_checksum_is_different file
+# | arg: file - The file on which the checksum test will be perfomed.
+#
+# | ret: Return the name a the backup file, or nothing
+ynh_backup_if_checksum_is_different () {
+	local file=$1
+	local checksum_setting_name=checksum_${file//[\/ ]/_}	# Replace all '/' and ' ' by '_'
+	local checksum_value=$(ynh_app_setting_get $app $checksum_setting_name)
+	if [ -n "$checksum_value" ]
+	then	# Proceed only if a value was stored into the app settings
+		if ! echo "$checksum_value $file" | sudo md5sum -c --status
+		then	# If the checksum is now different
+			backup_file="/home/yunohost.conf/backup/$file.backup.$(date '+%Y%m%d.%H%M%S')"
+			sudo mkdir -p "$(dirname "$backup_file")"
+			sudo cp -a "$file" "$backup_file"	# Backup the current file
+			echo "File $file has been manually modified since the installation or last upgrade. So it has been duplicated in $backup_file" >&2
+			echo "$backup_file"	# Return the name of the backup file
+		fi
+	fi
+}
+
 # Remove a file or a directory securely
 #
 # usage: ynh_secure_remove path_to_remove