Grouping (and Sequential Composition)

{} and ()

Calling commands through Sequential Composition like in echo hi ; ls -l ; cd .... ; is NOT grouping; each command is run one at a time and only the last one’s output is most recent

{ echo hi ; echo hello ; echo bye! ; }

• Calls the 3 commands and groups their outputs.
• However calling the 3 commands would look, in order, in the output is what its output is. (in our case, 3 separate lines for hi, hello, bye) You can also do this:

{ 
echo hi
echo hello } # note this } is counted towards the argument of "echo"
echo bye ; } > out.txt # The semicolon separates the lines; this } definitely ends the thingy. We also redirect the group to out.txt, so it will have:
> hi
> hello }
> bye
# inside of the file, literally

goes-in-cheat-sheet-DONE Or anything else similar

Subshells

Like {} except () is run in a totally new shell instance. The only thing that can be passed from () into our world is the exit code of the last command

( mkdir temporaryFolder ; ) # This will exit 0 first, then 1 when it already exists
 
( mkdir temporaryFolder ; echo hi! ) # This will exit 0 every time, since echo almost always works and it is the last run command!