Bash Sub Shells

“Creating sub-shells in bash is simple: just put the commands to
be run in the sub-shell inside parentheses. This causes bash to
start the commands as a separate process. This group of commands
essentially acts like a separate script file, their input/output
can be collectively redirected and/or they can be executed in the
background by following the closing parenthesis with an
ampersand.”

Complete
Story