yes, even more ksh prompt fun...
#tags mail

So the next thing that bothered me about my prompt was the fact that sometimes I'd have some crazy long directory filling up 90% of the line - this was a bad thing. So I set out along with my companion, <code>sed</code>, and together we squashed this beast.<br>
<pre>
[ -w "/" ] && Z="#" || Z=">"; export Z
PROMPT='$(A=$?; [ $A -ne 0 ] && A="!!{$A}!! " || A=""; SPWD=$(/bin/pwd | \
/usr/bin/sed -Ee "s,(/usr)?$HOME,~,; <b>s!!(/[^/]+/).*(/.{20,})$!!1...2!!</b>"); \
/bin/echo -n $HOST"("$SPWD") [!] ${A}${Z} " )'

case $TERM in
   aterm|xterm|dtterm)
      PROMPT=${PROMPT%)*}'; /bin/echo -n "^[]2;"$HOST"("$SPWD") [!] ${A}^G" 1>&2)'
      ;;
esac
PS1=$PROMPT
</pre>

The part marked in bold is what actually shortens the path. This will take what was previously a terribly long prompt and shorten the directory... ie;<br>
<code>/usr/local/lib/perl5/site_perl/5.6.1/Curses/UI/Dialog</code> 
<br>
will become
<br>
<code>/usr/.../5.6.1/Curses/UI/Dialog</code>
<p>

Oh, and this new feature actually makes the overal content of <code>$PS1</code> shorter by 3 characters! Instead of 257 characters, it's 254. This is due to a rewrite of part of the code - <code>pwd</code> and <code>sed</code> are only called one time now.