diff --git a/sql/bin/db-init b/sql/bin/db-init
--- a/sql/bin/db-init
+++ b/sql/bin/db-init
@@ -18,25 +18,33 @@
 DB_LOCALE="C.UTF-8"
 DB_TEMPLATE="template0"
 
+cd "$( dirname $0 )/.."
+
 if ! [ -f "$SQL_INIT" ] ; then
     echo "Cannot find $SQL_INIT. Abort."
-    echo "Note: db-init should usually be run from swh-storage/sql as bin/db-init."
     exit 2
 fi
 
-if [ -z "$1" -o -z "$2" -o -z "$3" ] ; then
-    echo "Usage: bin/db-init DB_PORT DB_NAME DB_USER"
-    echo "Example: bin/db-init 5432 softwareheritage-dev swhdev"
+if [ -z "$1" ] ; then
+    echo "Usage: bin/db-init DB_NAME [DB_USER [DB_PORT]]"
+    echo "Example: bin/db-init softwareheritage-dev"
     echo "Note: DB_NAME should not exist and will be created; DB_USER can exist."
     exit 2
 fi
-db_port="$1"
-db_name="$2"
-db_user="$3"
-conn_flags="--port ${db_port}"
+db_name="$1"
+db_user="${2:-$USER}"
+
+conn_flags=""
+if [ -n "$3" ]; then
+    conn_flags="--port $3"
+fi
 
-echo "I: creating Postgres user ${db_user} ..."
-createuser $conn_flags --pwprompt "$db_user" || true
+user_exists=$( psql postgres -tAc "SELECT 1 FROM pg_roles
+                                   WHERE rolname='$db_user'" )
+if [ "$user_exists" != "1" ]; then
+    echo "I: creating Postgres user ${db_user} ..."
+    createuser $conn_flags --pwprompt "$db_user" || true
+fi
 
 echo "I: creating Postgres database ${db_name} ..."
 createdb $conn_flags \