sauv_postgresql: correct return code with Bash

sauvegarde_postgresql.sh

@@ -1,4 +1,4 @@
-#!/bin/sh
+#!/bin/bash
 
 # Configuration
 # Le fichier sera nommé BASE_DIR/PREFIXEbasenameSUFFIXE
@@ -7,17 +7,27 @@ PREFIXE="sauv_pgsql"
 SUFFIXE=_$( date +%Y%m%d-%H%M ).sql.gz
 DUREE_DE_VIE=5
 
-# Vérifications initiales
+# Exit at first error
+# note : check that you receive crontab's mails in case something goes wrong.
+set -e
+if [ -n "$BASH" ]; then
+	# Bash required for this. If not available, return code will be 0
+	# even if pg_dumpall fails (but usually it write something on stderr
+	# so cron will send a mail nevertheless).
+	set -o pipefail
+fi
+
+# Initial checks
 if [ ! -d "$BASE_DIR" ]; then
 	echo "ERREUR : répertoire de sauvegarde inexistant : $BASE_DIR ." >&2
 	exit 1
 fi
 
-# Sauvegarde des bases
+# Backup of the whole default cluster
 su -l -c pg_dumpall postgres | gzip -c > "$BASE_DIR/$PREFIXE$SUFFIXE"
 
 
-# Suppression des anciennes bases
+# Deletion of old backups
 if [ "$1" = "--delete-olds" ]; then
 	find $BASE_DIR -name "$PREFIXE*" -mtime +$DUREE_DE_VIE -print0 | xargs -n 200 -r -0 rm -f
 fi