The writeto(fileName) function writes the output of all subsequently entered Maple commands into the file fileName.

When the command writeto(fileName) is entered, all subsequent commands have their results immediately stored in fileName. The results of these commands are not displayed on the screen. The command prompt and the input statements are also echoed into fileName (unless echoing is turned off via interface(echo=0) ).

The special command writeto(terminal) restores the standard mode of printing the results on the terminal.

If fileName already exists, the contents of the file are overwritten.

An alternative method of writing to a file is available by using the appendto(fileName) function. Rather than overwriting the contents (if any) of fileName, the new output is appended to fileName.

The writeto and appendto commands are thread safe as of Maple 15, however their effect is global, thus the most recent call will be in effect.  

If you want to call writeto or appendto to capture the output from multiple threads, your code must guarantee that outputting does not begin until after the call occurs.  Further you must guarantee that all outputting is complete before appendto or writeto is called a second time, otherwise some output may be written to the wrong file.