# More Shell Scripts, ‹make›

 1. In this lecture, we will learn more about writing shell scripts.
    We will also learn about makefiles, which primarily exist to
    automate compilation.
 2. But the first part will be about shell scripts, of the sort that
    we started with in the first lecture 2 weeks ago.
 3. We will learn about variables, conditionals, loops and a
    collection of small programs that make writing scripts much
    easier.
 4. There is no single ‘shell language’: instead, this is a family.
    The most important of various shells are those descended from
    the Bourne shell.
 5. POSIX mandates that ‹/bin/sh› is always a Bourne-compatible
    shell.
 6. That said, we will only deal with Bourne shells: GNU ‹bash› is
    one widely used implementation (the default ‹/bin/sh› on many
    Linuxes), some other are ‹ksh› and ‹dash›.
    
That said, let's get on with it:

    $ micro variables.sh