running scripts like oracle sqlplus

I have been trying to figure out how I can run a pgsql script like I can run a plsql script with oracle's sqlplus. 
Hereis a sample script file for what I want to run:<br /><br />declare<br />  sysuserid integer := 0;<br />  hwcustid 
integer:= 0;<br /> begin<br /><br />select nextval( 'user_seq' ) into  sysuserid;<br />select nextval( 'customer_seq'
) into hwcustid;<br /><br />insert into user<br />(<br />  user_id,<br />  customer_id,<br />  create_user,<br /> 
update_user<br/> )<br />values<br />(<br />  sysuserid,<br />  hwcustid,<br />  sysuserid,<br />  sysuserid<br />);<br
/><br/>insert into customer<br />(<br />  customer_id,<br />  create_user,<br />  update_user<br />)<br />values<br
/>(<br/>  hwcustid,<br />  sysuserid,<br />   sysuserid<br />);<br /><br />commit;  <br /><br />end;<br /><br />I try
torun the script in psql and thru pgadmin and cannot seem to make them work.  I do not want to turn it into a
function. I just want it to execute the block in a fashion similar to Oracle'sqlplus running @scriptfile.sql.<br /><br
/>Thanks<br/>