tty: Line wrapping

Terminals that support line wrapping, aka automatic margins ("am"), are likely to support escape sequences to toggle it:

tput rmam
# Line wrapping off (long lines are truncated at the RH margin)
# ...
tput smam
# Line wrapping on (long lines are wrapped at the RH margin)
# ...

See terminfo for more details of these escape codes.

To check whether your terminal supports automatic margins, list the capabilities with infocmp -1.