$() vs () bash

$() vs `` bash

$() or `` is called command subsitution

They are the same. Command subsitution allows the output of a command to 
replace the command identifier.

() vs {} bash

() 
- Placing a list of commands between parentheses causes a subshell environment
to be created, and each of the commands in list to be executed in that subshell.
Since the list is executed in a subshell, variable assignments do not remain 
in effect after the subshell completes.

{}
- Placing a list of commands between curly braces causes the list to be executed
in the current shell context. No subshell is created. The semicolon (or newline)
following list is required.

$() vs () bash

$(cmd) substitutes the result of cmd as a string, whereas (cmd; cmd) run a list of commands in a subprocess.

If you want to put the output of one or more commands into a variable use the $( cmd ) form.

However if you want to run a number of commands and treat them as a single unit use the () form.

The latter is useful when you want to run a set of commands in the background.

Source: stackoverflow.com

Similar codes

0 vote240 views1 answer
How to connect your repo to your vscode
Shell/Bash
0 vote658 views1 answer
ERROR: Cannot find command 'git' - do you have 'git' installed and in your PATH?
Shell/Bash
0 vote256 views2 answers
Hash sum mismatch ubuntu
Shell/Bash
-2 votes233 views2 answers
Linux time now command
Shell/Bash
0 vote258 views1 answer
History terminal commad getting limited
Shell/Bash
0 vote277 views1 answer
Intel hd 4000 ubuntu driver
Shell/Bash
1 vote241 views1 answer
Change user to sudo kali
Shell/Bash
0 vote240 views2 answers
Update arch on terminal
Shell/Bash
0 vote254 views1 answer
Rails scaffold
Shell/Bash
1 vote231 views1 answer
Pytorch conda environment
Shell/Bash