In psql, I want to go back up a line and edit my SQL from the line above. How would I accomplish this? I tried the up arrow to no avail. My only recourse is to exit psql and jump back in. 
For some context:
I want to go back to the line above and change SET dw1 = TRUE
I am ssh'd into the server using gitbash for windows
You haven't finished the command. Notice how the first line ends with =# while the second line ends with -#, which indicates that it's awaiting further text.
You need to end the command with a semicolon (;).
Once you're at a new line that starts with =# you can press up to retrieve the previous command.
Here's an example where I entered select 1<ENTER> followed by ;<ENTER> followed by <UP>:
db=# select 1
db-# ;
?column?
----------
1
(1 row)
db=# select 1
;