Linux and Unix Shell Programming

6.3. Grouping commands using () and {}

To run several commands as a group effort all at once, the shell provides two methods. You can either run the group in the current shell or in a subshell.

To run a list of commands in the current shell, separate each command with a command separator, and enclose the list with round brackets.

The general format is:

(command1; command2; . . ) 

To run a command in the subshell do exactly the same but use {} instead of (). The general format is:

{command1; command2; . .) 

I do not use these methods by themselves very often. The only time I use these grouping operators is in conjunction with the && or ||.

Going back to our comet script example, if the script comet failed I would probably want to execute two ...