Multiple stage file move?

Greetings all.

I need is a script that will move a file from one known dir to another, then grab another file from a different dir to replace it, and have absolutely zero clue how to do this.
Here's what I am trying to do:
A web client wants his site header image to change based on US holidays.
So, a script would grab the default header jpg, move it to a different dir somewhere on the site, then grab a header that has, say, a Christmas theme, and move that into the dir where the default one was. Make sense?

I could then make a cron job that exe's the script based on known holiday dates.

Your solution (you'll probably need to wrap some additional logic and error handling etc round this):

#!/bin/sh
THEMEDDIR=/export/home/httpd/themes
HTMLDIR=/export/home/httpd/htdocs
FILE=header.jpg
THEME=xmas

if [ -r $HTMLDIR/$FILE ]
then
  cp -p $HTMLDIR/$FILE $THEMEDIR/${FILE}.default
  cp $THEMEDIR/${FILE}.${THEME} $HTMLDIR/$FILE
fi

An alternative approach - use symbolic links:

#!/bin/sh
HTMLDIR=/export/home/httpd/htdocs
FILE=header.jpg
if [ -r ${HTMLDIR}/${FILE}.$1 ]
then
  rm -f ${HTMLDIR}/${FILE}
  ln -s ${HTMLDIR}/${FILE}.$1 ${HTMLDIR}/${FILE}
else
  echo "$1 version of $FILE not found!"
  exit 1
fi

Usage: scriptname.sh <theme>
Where theme is something like 'xmas' or 'default' etc.

Them just have a copy of the header.jpg file for each theme (eg header.jpg.xmas), including the plain one called header.jpg.default.
Run this script to switch to whatever one you need.

Awesome, thanks a lot. I'll give it a try.