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pkg/yqlib/doc/operators/comment-operators.md

@@ -10,6 +10,12 @@ This will assign the LHS nodes comments to the expression on the RHS. The RHS is
 ### relative form: `|=` 
 Similar to the plain form, however the RHS evaluates against each matching LHS node! This is useful if you want to set the comments as a relative expression of the node, for instance its value or path.
 
+{% hint style="warning" %}
+Note that versions prior to 4.18 require the 'eval/e' command to be specified. 
+
+`yq e <exp> <file>`
+{% endhint %}
+
 ## Set line comment
 Given a sample.yml file of:
 ```yaml