Usage: ruby merge_zsh_history_and_remove_duplicates.rb ~/.zsh_history_1 ~/.zsh_history_2 …

merge_zsh_history_and_remove_duplicates.rb

#!/bin/env rubyn
remove_duplicates = true
cmds = []
exclude = ['exit', /^(ls|l|ll)\s/, /^(ls|l|ll)$/]
history = {}

ARGV.each do |file|
  File.readlines(file).each do |line|
    time, cmd = line.encode('UTF-8').encode('UTF-8', invalid: :replace).split(';')
    timestamp = time.split(':')[1]&.strip || ''
    cmd ||= ''
    cmd.strip!
    timestamp.strip!
    next if timestamp.empty? || cmd.empty?

    next if exclude.any? && exclude.map { |pattern|
      cmd.match?(pattern) || nil
    }.reject(&:nil?).any?

    if remove_duplicates
      if cmds.include?(cmd)
        next
      else
        cmds << cmd
      end
    end

    history[timestamp.to_i] ||= []
    history[timestamp.to_i] << cmd
  end
end

history.sort.each do |timestamp, cmds|
  cmds.each_with_index do |cmd, i|
    puts ": #{timestamp}:#{i};#{cmd}"
  end
end