Passing a unix variable value to a Plsql function

UNIX for Advanced & Expert Users
1

Suppose I have a unix variable called RGNM which is holding a value. Now I want to call a plsql function in my script. THis plsql function takes one IN parameter. I want to pass my UNIX VARIABLE Value to the plsql function. Can i just give it by giving $RGNM in the function after calling sqlplus and function name.

Please help me

2 
$ v="cobroraj"
$ printf "set serverout on\nexec dbms_output.put_line('%s')\n" "$v"|sqlplus -s '/ as sysdba'
cobroraj

PL/SQL procedure successfully completed.