few days back I merged a dev branch to master by mistake & pushed with lot of commits. than for time being I created new branch from an old commit of master (before dev merge) named "master_old" & used this for deployment.
say master has commits 1,2,3,4,5 (3,4,5 are unwanted ones from dev)
master_old has commits 1,2,6,7,8
I want the master to have 1,2,6,7,8
now I want to switch back to master but I want master to be exact copy of current master_old (without changes from dev merge)
How to kind of reset master to master_old's code?
Let's keep it simple :