Make sure bash history is saved when using tmux

bash/environment

@@ -12,14 +12,16 @@ export GOPATH=$HOME/opt/go
 
 # don't put duplicate lines in the history. See bash(1) for more options
 # ... or force ignoredups and ignorespace
-HISTCONTROL=ignoredups:ignorespace
+export HISTCONTROL=ignoredups:erasedups:ignorespace
 
 # append to the history file, don't overwrite it
 shopt -s histappend
 
 # Use empty string for unlimited history
-HISTSIZE=
-HISTFILESIZE=
+export HISTSIZE=
+export HISTFILESIZE=
+export HISTTIMEFORMAT='%y-%m-%d %T λ '
+export PROMPT_COMMAND="history -a; history -c; history -r; $PROMPT_COMMAND"
 
 # check the window size after each command and, if necessary,
 # update the values of LINES and COLUMNS.