How to replace a path with another path in sed?

Question

I have a csh script (although I can change languages if it has any relevance) where I have to:

sed s/AAA/BBB/ file

The problem is that AAA and BBB are paths, and so contain '/'. AAA is fixed, so I can say:

sed s/\/A\/A\A/BBB/ file

However, BBB is based on variables, including $PWD. How do I escape the '/' in $PWD?

OR is there some other way I should be doing this entirely?

Answer 1

sed can use any separator instead of / in the s command. Just use something that is not encountered in your paths:

s+AAA+BBB+

and so on.

Alternatively (and if you don't want to guess), you can pre-process your path with sed to escape the slashes:

pwdesc=$(echo $PWD | sed 's_/_\/_g')

and then do what you need with $pwdesc.