@WHERE-IS-FILE <file name>
may be used to see if a file or a peripheral device such as a line printer, tape reader and so on is occupied by another user or free to use. One of the following messages are printed:
<file name> OPEN BY USER <user name> ON TERMINAL <n>
or
<file name> RESERVED BY RT PROGRAM <RT name>
or
<file name> FREE TO USE
If an RT program has opened the file the following messages is printed
<file name> OPENED BY USER RT ON TERMINAL 1
The parameter <file name>
may be any name defined name for a peripheral device or the name of a file in an entered directory.