Last active
February 23, 2026 12:14
-
-
Save YounesRahimi/dbede5a7d01b42a5e9bc56ac6f078669 to your computer and use it in GitHub Desktop.
to_jalali.sh — Bash script to convert Gregorian datetime (with timezone offset) to Jalali (Shamsi/Persian) calendar. Pure Python stdlib, no external dependencies. Supports microseconds and any UTC offset (e.g. +03:30). Usage: to_jalali.sh "2025-05-20 23:51:32.961770 +03:30"
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| #!/usr/bin/env bash | |
| # ───────────────────────────────────────────────────────────────────────────── | |
| # to_jalali.sh — Convert Gregorian datetime to Jalali (Shamsi/Persian) | |
| # | |
| # Supported input formats: | |
| # "2025-05-20 23:51:32.961770 +03:30" explicit offset | |
| # "2025-05-20T23:51:32.961770Z" UTC (Z suffix) | |
| # "2025-05-20T23:51:32Z" UTC, no microseconds | |
| # "2025-05-20 23:51:32.961770" no tz → implied Tehran (+03:30) | |
| # "2025-05-20" date only → implied Tehran, 00:00:00 | |
| # (no argument) current local time | |
| # | |
| # Usage: | |
| # to_jalali.sh "2025-05-20 23:51:32.961770 +03:30" | |
| # to_jalali.sh "2025-05-20T23:51:32Z" | |
| # to_jalali.sh "2025-05-20" | |
| # to_jalali.sh | |
| # ───────────────────────────────────────────────────────────────────────────── | |
| INPUT="${1:-}" | |
| python3 - "$INPUT" <<'PYEOF' | |
| import sys, re | |
| from datetime import datetime, timezone, timedelta | |
| TEHRAN_TZ = timezone(timedelta(hours=3, minutes=30)) | |
| # ── Conversion algorithm ───────────────────────────────────────────────────── | |
| def div(a, b): return int(a / b) | |
| def mod(a, b): return a - div(a, b) * b | |
| def gregorian_to_jalali(gy, gm, gd): | |
| """ | |
| Accurate Gregorian -> Jalali conversion (no external dependencies). | |
| Algorithm: arithmetic method with base offsets 1600 (Gregorian) / 979 (Jalali). | |
| Verified: 2024-03-20 -> 1403-01-01, 2025-05-20 -> 1404-02-30, | |
| 2025-03-21 -> 1404-01-01 (Nowruz 1404) | |
| """ | |
| g_y = gy - 1600 | |
| g_m = gm - 1 | |
| g_d = gd - 1 | |
| g_d_no = (365 * g_y | |
| + div(g_y + 3, 4) | |
| - div(g_y + 99, 100) | |
| + div(g_y + 399, 400)) | |
| for i in range(g_m): | |
| g_d_no += [31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31][i] | |
| if g_m > 1 and ((gy % 4 == 0 and gy % 100 != 0) or gy % 400 == 0): | |
| g_d_no += 1 # leap day | |
| g_d_no += g_d | |
| j_d_no = g_d_no - 79 | |
| j_np = div(j_d_no, 12053) | |
| j_d_no = mod(j_d_no, 12053) | |
| j_y = 979 + 33 * j_np + 4 * div(j_d_no, 1461) | |
| j_d_no = mod(j_d_no, 1461) | |
| if j_d_no >= 366: | |
| j_y += div(j_d_no - 1, 365) | |
| j_d_no = mod(j_d_no - 1, 365) | |
| j_m = 12 | |
| for i, days in enumerate([31, 31, 31, 31, 31, 31, 30, 30, 30, 30, 30, 29]): | |
| if i == 11: break | |
| if j_d_no < days: | |
| j_m = i + 1 | |
| break | |
| j_d_no -= days | |
| return j_y, j_m, j_d_no + 1 | |
| # ── Input parser ───────────────────────────────────────────────────────────── | |
| def parse_input(s): | |
| """ | |
| Parses all supported formats into an aware datetime. | |
| Missing timezone -> Tehran (+03:30). | |
| Missing time -> 00:00:00. | |
| """ | |
| p = re.match( | |
| r'^(\d{4}-\d{2}-\d{2})' # date (required) | |
| r'(?:[T ](\d{2}:\d{2}:\d{2}(?:\.\d+)?))?' # time (optional) | |
| r'\s*(Z|[+-]\d{2}:?\d{2})?$', # tz (optional) | |
| s.strip() | |
| ) | |
| if not p: | |
| raise ValueError( | |
| f"Cannot parse: '{s}'\n" | |
| "Supported formats:\n" | |
| " 2025-05-20 23:51:32.961770 +03:30\n" | |
| " 2025-05-20T23:51:32.961770Z\n" | |
| " 2025-05-20T23:51:32Z\n" | |
| " 2025-05-20 23:51:32.961770 (Tehran timezone implied)\n" | |
| " 2025-05-20 (Tehran timezone implied)\n" | |
| ) | |
| date_part = p.group(1) | |
| time_part = p.group(2) or "00:00:00" | |
| tz_raw = p.group(3) # None | 'Z' | '+03:30' | '+0330' | |
| fmt = "%Y-%m-%d %H:%M:%S.%f" if '.' in time_part else "%Y-%m-%d %H:%M:%S" | |
| naive_dt = datetime.strptime(f"{date_part} {time_part}", fmt) | |
| if tz_raw is None: | |
| tz = TEHRAN_TZ | |
| elif tz_raw == 'Z': | |
| tz = timezone.utc | |
| else: | |
| tz_str = re.sub(r'([+-]\d{2})(\d{2})$', r'\1:\2', tz_raw) # +0330 -> +03:30 | |
| sign = 1 if tz_str[0] == '+' else -1 | |
| th, tm = int(tz_str[1:3]), int(tz_str[4:6]) | |
| tz = timezone(timedelta(hours=sign * th, minutes=sign * tm)) | |
| return naive_dt.replace(tzinfo=tz) | |
| # ── Main ───────────────────────────────────────────────────────────────────── | |
| input_str = sys.argv[1] if len(sys.argv) > 1 and sys.argv[1] else "" | |
| try: | |
| dt = parse_input(input_str) if input_str else datetime.now().astimezone() | |
| except ValueError as e: | |
| print(f"Error: {e}", file=sys.stderr) | |
| sys.exit(1) | |
| jy, jm, jd = gregorian_to_jalali(dt.year, dt.month, dt.day) | |
| raw_offset = dt.strftime('%z') | |
| tz_display = f"{raw_offset[:3]}:{raw_offset[3:]}" if raw_offset else "+00:00" | |
| print(f"Gregorian : {dt.strftime('%Y-%m-%d %H:%M:%S.%f')} {tz_display}") | |
| print(f"Jalali : {jy:04d}-{jm:02d}-{jd:02d} {dt.strftime('%H:%M:%S.%f')} {tz_display}") | |
| PYEOF |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment