Realistically, no.
echo $a.$b
first concatenates $a
and $b
into a new string, then passes it as a parameter to echo
, which prints it out.
echo $a,$b
gives two parameters to echo
, which will print both out.
The latter is slightly more efficient. Not in any way that you would normally notice though.
There is a difference in how it is evaluated. echo $a, $b
is like writing echo $a; echo $b;
, two separate calls. $b
will be evaluated after $a
is echo
'd. This can make a difference if your arguments are function calls which themselves echo
something, but again, in practice this should be irrelevant, since it's bad practice.