IDL has a facility called DOC_LIBRARY which you can use to get the
details of any procedure that you know the name of by typing:
IDL> doc_library,'yodat'
This will obtain a listing of the header information of
the program YODAT (any comments put in at the beginning
of the code between `;+' and `;-') provided it is in your
path. Wild cards are allowable, e.g.,
IDL> doc_library,'test*'
DOC_LIBRARY is a script driven program (i.e., it will work on ordinary
terminals as well as X-terminals or workstations. Do not include the
`.PRO' in the call to DOC_LIBRARY.