they start a subshell with parentheses:
and only redirect once to
But a subshell takes an extra process and takes time to start on a busy
If all you need to do is redirect output (or input) of a set of
commands, use the Bourne shell's list operators
Notice the spaces and the extra RETURN at the end. Each command must be separated from others. You can also write (note the semicolon after the last command):
Here are two other differences between the subshell (parentheses) and list (curly braces) operators. A cd command in the subshell doesn't change the parent shell's current directory; it does in a list. Also, a variable set in a subshell isn't passed to the parent shell; from a list, the variable is passed out.