Escaping double quotes in sed

[cj13579]

I am trying to replace a line in a file with something stored in a variable using sed but am having some difficulty because both the line I want to replace and the new line contain double quotes. I think that I have found the answer to my question in this stackoverflow thread but I'll be honest, I don't understand the answer given.

I am trying to replace this:

<transition on="success" to="viewLoginForm" />

With this:

<transition on="success" to="remoteAuthenticate" />

At the moment I have the following but it isn't working:

_LOGIN='<transition on="success" to="remoteAuthenticate" />'
sed -e "/<transition on="success" to="viewLoginForm" \/>/i ${_LOGIN}" /tmp/login-webflow.xml

I know that my problem stems from the fact that I am using a variable and I can get it working hard coding it and using single quotes but I want to avoid that if possible.

I would be very grateful if someone could help me to understand the stackoverflow answer or even better, provide me an example of what I am looking to do

Many thanks!

[Vaphell]

$ string='blabla<transition on="success" to="viewLoginForm" />xoxoxo'
$ login='<transition on="success" to="remoteAuthenticate" />'
$ echo "$string" | sed 's:<transition on="success" to="viewLoginForm" />:'"$login"':g'
blabla<transition on="success" to="remoteAuthenticate" />xoxoxo

[cj13579]

Ah ha, excellent. I think that will work for me.

Thank you very much for the quick response!