Convert Bash history to Zsh history

bash-to-zsh-hist.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-
# 
# This is how I used it:
# $ cat ~/.bash_history | python bash-to-zsh-hist.py >> ~/.zsh_history

import sys
import time


def main():
    timestamp = None
    for line in sys.stdin.readlines():
        line = line.rstrip('\n')
        if line.startswith('#') and timestamp is None:
            t = line[1:]
            if t.isdigit():
                timestamp = t
                continue
        else:
            sys.stdout.write(': %s:0;%s\n' % (timestamp or time.time(), line))
            timestamp = None


if __name__ == '__main__':
    main()

Updating the code to add bash history before zsh history.
I also code a function to joint bash command compound with \n (enter), like bash loops or ctrl+v command.

from sys import stdin, stdout

TIMESTAMP_FIRST_ZSH_CMD = 1737556882

def treat_enter(lines):
    fixed_lines = []
    full_cmd = ""
    count = 0
    while count < len(lines):
        full_cmd += lines[count].strip()
        if count == len(lines) - 1 or not lines[count+1].startswith(" ") or not lines[count].endswith("\n"):
            fixed_lines.append(full_cmd)
            full_cmd = ""
        count += 1
    return fixed_lines

def main():
    lines = stdin.readlines()
    # print(f"Before Treat: {len(lines)} lines")
    lines = treat_enter(lines)
    # print(f"After Treat: {len(lines)} lines")
    count_tt = TIMESTAMP_FIRST_ZSH_CMD - len(lines)
    for line in lines:
        line = line.rstrip('\n')
        stdout.write(": %s:0;%s\n" % (count_tt, line))
        count_tt += 1

if __name__ == "__main__":
    main()

To use this command:

Update the TIMESTAMP_FIRST_ZSH_CMD code variable with timestamp of the oldest zsh command.

cat ~/.bash_history | python3 code.py > ~/.zsh_history_new && cat ~/.zsh_history >> ~/.zsh_history_new

The file ~/.zsh_history_new will be created.