Lets say you had a web page and you wanted to change the css at certain times to show a new picture. Here’s some sed regexp’s to do it for ya.
In this example, I am picking a random image from a directory of approved images and switching out the old whatever.jpg with newstuff.jpg
heres the line i am going to be editing (actually the background of my site):
mv style.css style.css.bak
sed "s/img\/backs\/./img\/backs\/$file);/" style.css.bak > style.css```
Very useful for changing the background of a site by just setting up a cron job to change it whenever you like.