added postgresql backup script

pg_bak.sh

@@ -0,0 +1,27 @@
+#!/bin/bash
+
+bakpath="/srv/backup"
+count="5"
+num=$count
+
+cd $bakpath
+
+while [ -a daily0.dump ]; do
+    if [ -a daily$num.dump ]; then
+        echo "moving daily$num.dump to daily$((num+1)).dump"
+        mv daily$num.dump daily$((num+1)).dump
+    fi
+    num=$((num-1))
+done
+
+echo "dumping postgresql dbs to a new daily0.dump"
+sudo -u postgres pg_dumpall > daily0.dump
+
+if [ -a daily$((count+1)).dump ]; then
+    rm daily$((count+1)).dump
+    echo "removing daily$((count+1)).dump"
+fi
+
+echo "done"
+
+exit 0