# Grouping commands in a subshell

## Synopsis

    ( <LIST> )

## Description

The [list](../../syntax/basicgrammar.md#lists) `<LIST>` is executed in a
separate shell - a subprocess. No changes to the environment (variables
etc...) are reflected in the "main shell".

## Examples

Execute a command in a different directory.

``` bash
echo "$PWD"
( cd /usr; echo "$PWD" )
echo "$PWD" # Still in the original directory.
```

## Portability considerations

-   The subshell compound command is specified by POSIX.
-   Avoid ambiguous syntax.

``` bash
(((1+1))) # Equivalent to: (( (1+1) ))
```

## See also

-   [grouping commands](../../syntax/ccmd/grouping_plain.md)
-   [Subshells on Greycat's wiki](http://mywiki.wooledge.org/SubShell)