What does Rules token "node:unchanged" mean?

Question

I am on Drupal 7 and I am using the Rules module to do some stuff.

I must say that I am not very used to using this module; there are few questions that need answers, such as the use of the node:unchanged token.

For example, when I set a rule with a data comparison as a condition, I have to give the name of the referred field; then, there is either node:changed or node:unchanged.

I am quite accustomed to using node:changed. What does node:unchanged mean?

Answer 1

Terminology

"unchanged refers to the value before something (eg, a field of entity user or node) gets updated (the old value that it used to be).

"changed refers to the value after something (eg, a field of entity user or node) gets updated (the new value that it will become).

Examples

Have a look at my answers to these question for some typical usecases of it:

• Monitoring field changes in custom content type
• How to implement admin verification for selected user profile fields?
• How to include only an updated custom field in an email created using Rules?
• How to use Rules to email users when any field(s) is changed in a node (and include the unchanged/changed values for that field)?

Answer 2

"Unchanged" is literally the opposite of "changed" in this context. If you know what node:changed means, just reverse it for node:unchanged.

For reference, though:

• node:changed refers to a node after field or property data has been changed, following a node save
• node:unchanged refers to the same node, before field or property data has been changed.

The two are useful together for determining whether a particular field or property value has been changed on a node, and what the value went from/to, in a particular save operation.