Stephen Hawking: I would like to know a unifed theory of gravity and the other forces. Which of the big question would you like to know the answer to and why ?
Mark Zuckerberg: That's a pretty good one!
I'm most interested in questions about people. What will enable us live forever? How do we cure all diseases? How does the brain work? How does learning work and how we can empower humans to learn million times mores?
I also curious about whether there is a fundamental mathematical law underlying human social relationships that governs the balance of who and what we all care about. I bet there is.1
$1, $2, $3, ... are the positional parameters.
$@ is an array-like construct of all positional parameters, {$1, $2, $3 ...}.
$* is the IFS expansion of all positional parameters, $1 $2 $3 ....
$# is the number of positional parameters.
$- current options set for the shell.
$$ pid of the current shell (not subshell).
$_ most recent parameter (or the abs path of the command to start the current shell immediately after startup).
$IFS is the (input) field separator.
$? is the most recent foreground pipeline exit status.
$! is the PID of the most recent background command.
$0 is the name of the shell or shell script.
Mark Zuckerberg: That's a pretty good one! I'm most interested in questions about people. What will enable us live forever? How do we cure all diseases? How does the brain work? How does learning work and how we can empower humans to learn million times mores? I also curious about whether there is a fundamental mathematical law underlying human social relationships that governs the balance of who and what we all care about. I bet there is.1