You can set the env variable SQLPATH pointing to all the directories containing your scripts.
In this way you can call your scripts everytime simply using an @ without specifing the script destination path.
However if your script is in the current directory and it is not spiecified in the SQLPATH env variable you can call it using a double @ (example @@myscript)
Remember that this variable is only read by SQLPLUS and not by SVRMGR
Bye.