The article is wrong in it’s title.
A single judge cannot make a “permanent” block on Trump’s order. Such a block would/will be appealed to the full circuit court, and if it upholds that one judge it would be appealed to the SCOTUS.
The judge’s ruling itself is just one temporary legal step in what can be a long process. At this point it cannot be said to be “permanent”.
It’s permanent until overturned
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It’s permanent, in that it doesn’t have an expiration date.
As you note, it’s impermanent, in that it is only his ruling.