I think that you can code a simple script or PL/SQL to get all constraint name from USER_CONSTRAINTS dictionary or DBA_CONSTRAINTS dictionary.

For UNIX, following is a simple method to disable all user constraints.

Create a shell script

#!/bin/sh
(
SQLPLUS -S /NOLOG <<-EOF
CONNECT USERID/PASSWORD
SET FEEDBACK OFF
SET PAGESIZE 0
SELECT CONSTRAINT_NAME FROM USER_CONSTRAINTS
EOF
) | while read constraint_name
do
echo "ALTER ${constraint_name} DISABLE NOVALIDATE
done | sqlplus userid/passwd

If you want to perform more advanced functions, I suggest that you can use PL/SQL instead.