I installed Sierra OS on my iMac without any troubles. But, when I open Terminal, I can't scroll through the bash history when pressing the up arrow.
Have a look at
/etc/bashrc_Apple_Terminal. The file contains comments that explain how to disable bash_sessions:
# The save/restore mechanism is disabled if the following file exists: # # ~/.bash_sessions_disable
or just disable their shell history mechanism
# You may disable this behavior and share a single history by setting # SHELL_SESSION_HISTORY to 0. There are some common user customizations # that arrange to share new commands among running shells by # manipulating the history at each prompt, and they typically include # 'shopt -s histappend'; therefore, if the histappend shell option is # enabled, per-session history is disabled by default. You may # explicitly enable it by setting SHELL_SESSION_HISTORY to 1.
You can perhaps also restore the (hidden) .bash_history file from the TimeMachine backup Found in the HomeFolder.