[Windflier]

For all intensive purposes

For all intents and purposes.

[1Old Pro]

for all intensive purposes. While people generally use both for all intents and purposes and for all intensive purposes to mean “in every practical sense,” ”seeming as if,” or “virtually/almost completely,” the standard form of the idiom is for all intents and purposes

That's how I learnt it.

[Svartalfiar]

For all intensive purposes

For all intents and purposes.

For all in tents, and porpoises.

[JPJones]

For all in tents and porpoises.