“Grammar is the difference between knowing your shit and knowing you’re shit”

“Grammar: The difference between knowing your shit and knowing you’re shit” is a jocular saying that has been printed on many images. “Knowing about spelling is the difference between knowing your shit and not knowing you’re shit” was posted on Twitter on October 11, 2010.
 
“Grammar is the difference between knowing your shit and knowing you’re shit” was posted on Twitter on August 23, 2011.
     
 
Twitter
Steven Alexander‏
@stv242
Replying to @technoluxe
@avitania Capitalization LOL. It’s like knowing your shit vs. knowing you’re shit.
3:13 AM - 27 Aug 2010
 
Twitter
Steve‏
@BergerofLondon
Knowing about spelling is the difference between knowing your shit and not knowing you’re shit.
4:24 AM - 11 Oct 2010
 
Twitter
Ernie Oporto‏
@shokk
Spelling. It’s the difference between knowing your shit and knowing you’re shit.
7:40 AM - 20 Aug 2011
 
Twitter
jebgavin‏
@jebgavin
Grammar is the difference between knowing your shit and knowing you’re shit.
5:44 PM - 23 Aug 2011
 
Twitter
George Buckingham‏
@gbuckingham89
Grammar can be the difference between knowing your shit and knowing you’re shit.
6:36 AM - 26 Aug 2011
 
Google Books
Evolve Or Die Single a No Bs Guide to Dating
By Michelle Roman Higgins
Victoria, BC: FriesenPress
2012
Pg. 40:
Grammar: it’s the difference between knowing your shit and knowing you’re shit.
 
Google Groups: alt.usage.english
The difference…
MC
2/18/12
There’s a saying floating around Facebook:
 
Grammar: The difference between knowing your shit and knowing you’re shit.
     
Twitter
Bill Murray‏
@BiIIMurray
Grammar - The difference between knowing your shit, and knowing you’re shit.
3:27 PM - 3 Jul 2013
 
BuzzFeed
19 Jokes Only Grammar Nerds Will Understand
The difference between knowing you’re shit and knowing your shit.
Posted on September 3, 2013, at 2:04 p.m.
Anna Klassen
BuzzFeed Contributor
(...)
5. Grammar: the difference between knowing your shit and knowing you’re shit.
 
Google Books
Grammar: Know Your Shit or Know You’re Shit
By Joanne Adams
Chichester, West Sussex: Summersdale Publishers Ltd
2015
Pg. ?:
If you take away one thing from this book, it needs to be this; after all, good punctuation is the difference between knowing your shit and knowing you’re shit, as they say.