perlpacktut: Remove some jargon, flesh out

Fixes #22697

Author: khwilliamson

pod/perlpacktut.pod

@@ -41,11 +41,10 @@ of these two functions.
 
 To see how (un)packing works, we'll start with a simple template
 code where the conversion is in low gear: between the contents of a byte
-sequence and a string of hexadecimal digits. Let's use C<unpack>, since
-this is likely to remind you of a dump program, or some desperate last
-message unfortunate programs are wont to throw at you before they expire
-into the wild blue yonder. Assuming that the variable C<$mem> holds a 
-sequence of bytes that we'd like to inspect without assuming anything 
+sequence and a string of hexadecimal digits.  The example we've chosen
+looks like a crash dump, and shows how C<unpack> can be used to make
+sense of things like this.  Assuming that the variable C<$mem> holds a
+sequence of bytes that we'd like to inspect without assuming anything
 about its meaning, we can write
 
    my( $hex ) = unpack( 'H*', $mem );
@@ -58,17 +57,21 @@ corresponding to a byte:
 
 What was in this chunk of memory? Numbers, characters, or a mixture of
 both? Assuming that we're on a computer where ASCII (or some similar)
-encoding is used: hexadecimal values in the range C<0x40> - C<0x5A>
+encoding is used: hexadecimal values in the range C<0x41> - C<0x5A>
 indicate an uppercase letter, and C<0x20> encodes a space. So we might
-assume it is a piece of text, which some are able to read like a tabloid;
-but others will have to get hold of an ASCII table and relive that
-firstgrader feeling. Not caring too much about which way to read this,
+assume it is a piece of ASCII text.  We can verify that by doing
+
+ print unpack( 'A*', $mem), "\n"
+
+ A MAN A PLAN A CANAL PANAMA
+
+Going back to the original C<H*> for the purposes of this tutorial,
 we note that C<unpack> with the template code C<H> converts the contents
 of a sequence of bytes into the customary hexadecimal notation. Since
 "a sequence of" is a pretty vague indication of quantity, C<H> has been
 defined to convert just a single hexadecimal digit unless it is followed
 by a repeat count. An asterisk for the repeat count means to use whatever
-remains.
+remains.  That is also the case for the C<A*> above.
 
 The inverse operation - packing byte contents from a string of hexadecimal
 digits - is just as easily written. For instance: