STEP    CODE                            MEANING                             IT IS NOW...
1       &main();                        call 'main', no arguments           undef
2       my @mylist = qw(a b c);         create and define @mylist           undef
3       foreach(@mylist)                iterate over @mylist                undef

    3a                                  iteration 1                         it is now "a"
4       &fun($_);                       &fun(it)                            "a"
5       open(STATUS, "echo d-e-f|");    echo "d-e-f" into new fh STATUS     "a"
6       while (<STATUS>)                sequentially read lines             "a"
    6a                                  iteration 1: read it.               it is now "d-e-f"
7       if (/d-e-f/)                    if it matches (and it does),        "d-e-f"
8       close(STATUS)                   close the FH                        "d-e-f"
9       return;                         go back to whence we came           "d-e-f"
10      print "changed: \$_ $_\n"       print it                            "d-e-f"

    3b                                  iteration 2                         it is now "b"
...snip...