Saving or Grouping Output from Several Commands in bash

You want to capture the output with a redirect, but you’re typing several commands on one line.

The final redirect applies only to the last command, the last ls on that line. All the other output appears on the screen (i.e., does not get redirected).

Use braces { } to group these commands together, then redirection applies to the output from all commands in the group. For example:

Alternately, you could use parentheses ( ) to tell bash to run the commands in a subshell, then redirect the output of the entire subshell’s execution.

For example:

While these two solutions look very similar, there are two important differences. The first difference is syntactic, the second is semantic.

Syntactically, the braces need to have whitespace around them and the last command inside the list must terminate
with a semicolon.

That’s not required when you use parentheses. The bigger difference, though, is semantic—what these constructs mean.

The braces are just a way to group several commands together, more like a shorthand for our redirecting, so that
we don’t have to redirect each command separately.

Commands enclosed in parentheses, however, run in another instance of the shell, a child of the current shell
called a subshell.
The subshell is almost identical to the current shell’s environment, i.e., variables, including $PATH, are all the same, but traps are handled differently .

Now here is the big difference in using the subshell approach: because a subshell is used to execute the cd commands, when the subshell exits, your main shell is back where it started, i.e., its current directory
hasn’t moved, and its variables haven’t changed.
With the braces used for grouping, you end up in the new directory (../elsewhere in our example).

Any other changes that you make (variable assignments, for example) will be made to your current shell instance.

While both approaches result in the same output, they leave you in very different places.
One interesting thing you can do with braces is form more concise branching blocks . You can shorten this:

into this: