Since you're coming to xs from another shell, there are some things that
you'll need to know. There's a lot more in TUTORIAL.md .

  * ~/.xsrc is executed only when xs starts as a login shell.
  * ~/.xsin is executed when xs starts as an interactive shell. If xs is
    also a login shell, ~/.xsrc runs first.
  * Substitution inside of a word is done using caret (^) for concatenation,
    e.g.:
    'foo is '^$foo
    and
    'My File.'^*
    xs will also insert a caret when it can do so unambiguously (see Free
    Carets in xs(1)). Thus the above may be written without carets.
  * Use the <= operator to run a command and get its exit code.
  * The concatenation operator generates the cross-product of lists, e.g.:
    ls foo.^[ch]
    and
    ls bar.^(cxx hxx) .
  * Redirection and piping of stdin/stdout is as you'd expect; there's an
    xs-specfic syntax for all other redirection operations (redirect stderr,
    duplicate a descriptor, close a descriptor).
  * Beware trampolines to builtin commands for other shells, e.g. bash's
    /usr/bin/read.
