Getting and suppressing console output

The GCL will only print output at the console if you explicity ask for it with the built-in function Print. This function has the prototype

Print[x->T] =: T
for any data type T, and has the short form << x. You may have noticed that the GCL prompt concludes with a <<. In fact, this is not part of the prompt, but rather is a ``pre-typed'' part of your GCL command.

Once you have become accustomed to the GCL, you may prefer to supress output from some or all commands typed at the GCL command line. This can be done for individual commands by using the backspace or delete keys to erase the << part of the prompt. The built-in function SetVerbose controls whether << is pretyped at every prompt. The command

SetVerbose[False]
will turn off this feature, so that your prompt will then look as follows:
GCL1:= 
Now, the default is that no output is printed. If you want to have the output of specific commands printed, then you can start your command with <<. For example,
GCL1:= 1+1
GCL2:= << 1+1
2
Note that error messages will be reported at the console regardless of the setting of the verbose mode.