Use this command to determine if a file was opened in Read mode, i.e. for reading data from. Files that are opened in read mode cannot be written to, and vice-versa.
|ID of file previously opened with fileOpen
// Obtain file ID earlier do some operation to the file
// See if the file was opened in "Read Mode"
if( `isFileReadable $fileID` == true )
print "Can read from the file"; else print "Cannot read from the file";