Persist zsh command history

.zshrc

@@ -5,6 +5,15 @@ if [ -x /home/linuxbrew/.linuxbrew/bin/brew ]; then
 fi
 export PATH="$HOME/.local/bin:$PATH"
 
+# Persistent command history. Keep HISTSIZE larger than SAVEHIST so zsh has
+# room to merge history from other active shells before trimming the file.
+HISTFILE="$HOME/.zsh_history"
+HISTSIZE=100000
+SAVEHIST=80000
+setopt APPEND_HISTORY
+setopt SHARE_HISTORY
+setopt HIST_REDUCE_BLANKS
+
 # ===================== User-tunable environment ========================
 # Single place to control the look of the whole stack.
 export KANAGAWA_THEME="wave"            # wave | dragon