The following Avenue script displays an ASCII text file in a pop-up window.
myFile = LineFile.Make("<ascii_text_file_name".AsFilename,#FILE_PERM_READ)
VeryLongString = myFile.ReadElt
VeryLongString = VeryLongString + NL + myFile.ReadElt
Replace the text "<ascii_text_file_name>" with the path to the text file you would like view.