Add to .zshrc file for reverse-i-search on command history:

export HISTFILE=~/.zsh_history
export HISTSIZE=1000000
export SAVEHIST=1000000
setopt INC_APPEND_HISTORY
setopt HIST_FIND_NO_DUPS
setopt HIST_IGNORE_ALL_DUPS
setopt HIST_IGNORE_SPACE

export HISTFILE — Location of history file

export HISTSIZE — Size of the history file to be kept on disk (number of lines)

export SAVEHIST — Size of the history file to be kept in RAM for faster searches (has no performance impact on modern hardware)

NC_APPEND_HISTORY — Append commands to the shell history immediately, rather than on exit

HIST_FIND_NO_DUPS — Will skip duplicates when using arrow keys to navigate recent commands

HIST_IGNORE_ALL_DUPS — Will not append duplicate commands to the history file

HIST_IGNORE_SPACE — Will not append a command that begins with a space to the history file, for example ` export ENV_VAR=”XXXXXXXXXX”`