I checked - it's pgs. 152-156. They call their utility "overwrite".
"...Many other commands could also use a -o command. For example, sed could edit a file in place: ... It would be impractical to modify all such commands to add the option. Furthermore, it would be bad design: it is better to centralize functions, as the shell does with the > operator."
"...Many other commands could also use a -o command. For example, sed could edit a file in place: ... It would be impractical to modify all such commands to add the option. Furthermore, it would be bad design: it is better to centralize functions, as the shell does with the > operator."