Updated SC2087 (markdown)

SC2087.md

@@ -14,11 +14,23 @@
 
 ### Rationale:
 
-When the end token of a here document is not quoted, parameter expansions and command substitutions will be expanded. This means that the hostname printed will be that of the client, and not of the server.
+When the end token of a here document is unquoted, parameter expansion and command substitution will happen on in contents of the here doc. 
 
-In other words, before sending the commands to the server, the client replaces `$HOSTNAME` with localhost, thereby sending `echo "Logged in on localhost"` to the server.
+This means that before sending the commands to the server, the client replaces `$HOSTNAME` with localhost, thereby sending `echo "Logged in on localhost"` to the server. This has the effect of printing the client's hostname instead of the server's. 
 
-By quoting the here token, local expansion will not take place, so the server sees `echo "Logged in on $HOSTNAME"` which is expanded and printed with the server's hostname, which is usually the intention.
+Scripts with any kind of variable use are especially problematic because all references will be expanded before the script run. For example,
+
+    ssh host << EOF
+      x="$(uname -a)"
+      echo "$x"
+    EOF
+
+will never print anything, neither client nor server details, since before evaluation, it will be expanded to:
+
+      x="Linux localhost ... x86_64 GNU/Linux"
+      echo ""
+
+By quoting the here token, local expansion will not take place, so the server sees `echo "Logged in on $HOSTNAME"` which is expanded and printed with the server's hostname, which is usually the intention. 
 
 ### Exceptions: