explanation of this line

Hi Gurus,
sqlplus system @$1 0</opt/oracle/pwdfile

What would be the output of the above life....the password for the user "system" the user is stored in /opt/oracle/pwdfile

When i try to run the script it says password not found?

$1 0<

What is the meaning of the $1 and 0?

Many Thanks,

The @ symbol is used to execute sql scripts, I think (I am no DBA). The $1 stands for the first argument that is sent in to the script that is being executed. The 0 stands for standard input. '0 < somefile' means that the script has to take input from the file instead of standard input.