1.They’re escape sequences.
is a newline and
is a carriage return.
In Windows most text editors have a newline as
and on unix it’s
.
2.
is the carriage return
is the newline
These are available in many other languages aside from PHP.
3.They’re “carriage return” and “line feed” respectively. Typically on Windows, you need both together to represent a line terminator: ”
” whereas on most (all?) Unix systems, ”
” is enough.