bash-hackers-wiki/docs/syntax/ccmd/grouping_subshell.md

# 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)
Convert syntax pages to Markdown 2023-07-05 11:43:35 +02:00			`# Grouping commands in a subshell`

			`## Synopsis`

			`( <LIST> )`

			`## Description`

Fix hyperlinks of markdown pages at depth 3 find docs/ -depth 3 -name '.md' \| xargs grep '(./' -l \| \ xargs -I{} \ sed -i '' \ -e 's%(/\([^/#).][^/#).]\)/\([^/#).][^/#).]\)\(.md\)\{0\})%(../../\1/\2.md)%g' \ -e 's%(/\([^/#).][^/#).]\)/\([^/#).][^/#).]\)#\([a-zA-Z_-][0-9a-zA-Z_-]\))%(../../\1/\2.md#\3)%g' \ -e 's%(/\([^/#).][^/#).]\)/\([^/#).][^/#).]\)/\([^/#).][^/#).]\)\(.md\)\{0\})%(../../\1/\2/\3.md)%g' \ -e 's%(/\([^/#).][^/#).]\)/\([^/#).][^/#).]\)/\([^/#).][^/#).]\)#\([a-zA-Z_-][0-9a-zA-Z_-]\))%(../../\1/\2/\3.md#\4)%g' \ -e 's%](\([^:.>)#][^:.>)#]\))%](../../\1.md)%g' \ -e 's%](\([^:.>)#][^:.>)#]\)#\([^:.>)#][^:.>)#]*\))%](../../\1.md#\2)%g' \ {} Related to https://github.com/flokoe/bash-hackers-wiki/issues/10 2024-01-29 02:07:56 +01:00			The [list](../../syntax/basicgrammar.md#lists) `<LIST>` is executed in a
Convert syntax pages to Markdown 2023-07-05 11:43:35 +02:00			`separate shell - a subprocess. No changes to the environment (variables`
Updated table formatting, call-outs, html comments, improper escapes. 2024-10-08 06:00:17 +02:00			`etc...) are reflected in the "main shell".`
Convert syntax pages to Markdown 2023-07-05 11:43:35 +02:00
			`## 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`

Fix hyperlinks of markdown pages at depth 3 find docs/ -depth 3 -name '.md' \| xargs grep '(./' -l \| \ xargs -I{} \ sed -i '' \ -e 's%(/\([^/#).][^/#).]\)/\([^/#).][^/#).]\)\(.md\)\{0\})%(../../\1/\2.md)%g' \ -e 's%(/\([^/#).][^/#).]\)/\([^/#).][^/#).]\)#\([a-zA-Z_-][0-9a-zA-Z_-]\))%(../../\1/\2.md#\3)%g' \ -e 's%(/\([^/#).][^/#).]\)/\([^/#).][^/#).]\)/\([^/#).][^/#).]\)\(.md\)\{0\})%(../../\1/\2/\3.md)%g' \ -e 's%(/\([^/#).][^/#).]\)/\([^/#).][^/#).]\)/\([^/#).][^/#).]\)#\([a-zA-Z_-][0-9a-zA-Z_-]\))%(../../\1/\2/\3.md#\4)%g' \ -e 's%](\([^:.>)#][^:.>)#]\))%](../../\1.md)%g' \ -e 's%](\([^:.>)#][^:.>)#]\)#\([^:.>)#][^:.>)#]*\))%](../../\1.md#\2)%g' \ {} Related to https://github.com/flokoe/bash-hackers-wiki/issues/10 2024-01-29 02:07:56 +01:00			`- [grouping commands](../../syntax/ccmd/grouping_plain.md)`
format(docs): remove escaped 's character pairs 2024-03-30 19:22:45 +01:00			`- [Subshells on Greycat's wiki](http://mywiki.wooledge.org/SubShell)`