Thank you for replying, I solved this problem by the inspiration from you!
Firstly I ran something like below inside the local git directory to get the latest version of .sql from gitfarm
system('git pull')
Now that I have the latest version of .sql (let's call it tt.sql) inside this folder, I used either two of below to read the tt.sql into a str, and then I am good to go
fileName <- paste0(dir_sql_folder,'tt.sql')
a=readChar(fileName, file.info(fileName)$size)
fileName <- paste0(dir_sql_folder,'tt.sql')
a=system(paste('cat',fileName),intern = T)
Thanks for your help one more time, and if you have time, there is another consecutive problem that I encountered related to regex saved in str. Have a good day!