This is for debian but can be adapted with little trickery to any Linux distro. This enables changing the root of a shell so that the directories displayed are not too long.

Useful for dir-verbose frameworks like symfony or when managing a huge website directory.

Usage: setroot $PWD

function setroot
{
web_root=$1
PS1='${debian_chroot:+($debian_chroot)}\u@\h:$(echo \w| sed s@'$web_root'@@g)\$ \[\033k\]$(basename "\w")\[\033\\\]'
export PS1
alias ca="cd $PWD"
}
 
# this can be adapted