grouping.md

Grouping commands

Use { commands } or ( commands )

Within same shell

# Avoids redirecting each command individually.
{
  echo "PASSWD follows"
  cat /etc/passwd
  echo
  echo "GROUPS follows"
  cat /etc/group
} >output.txt

# One liner: spaces around braces. last command terminated with ;
{ echo foo; cat somefile; echo bar; } > output.txt

# Any properly terminated compound command will work without an extra terminator.
{ while sleep 1; do echo ZzZzzZ; done }

Body of a function:

print_help() {
  echo "Options:"
  echo "-h           This help text"
  echo "-f FILE      Use config file FILE"
  echo "-u USER      Run as user USER"
}

Within a subshell

Example: Execute a command in a different directory.

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