System Time

Get accurate system time information in multiple formats.

Quick Usage

Current Time (Local)

date                                    # Human readable
date -Iseconds                          # ISO 8601 with seconds
date +%s                                # Unix timestamp

Current Time (UTC)

date -u                                 # UTC human readable
date -u -Iseconds                       # UTC ISO 8601
date -u +%s                             # UTC Unix timestamp (same as local)

Specific Timezone

TZ=Asia/Shanghai date                   # Shanghai time
TZ=America/New_York date                # New York time
TZ=Europe/London date                   # London time

Common Formats

| Format | Command | Example Output | |--------|---------|----------------| | ISO 8601 | date -Iseconds | 2024-03-11T16:30:00+08:00 | | Unix timestamp | date +%s | 1710145800 | | RFC 2822 | date -R | Mon, 11 Mar 2024 16:30:00 +0800 | | Custom | date "+%Y-%m-%d %H:%M:%S" | 2024-03-11 16:30:00 |

Timezone Conversion

Convert from one timezone to another:

# Convert specific time from Shanghai to New York
TZ=America/New_York date -d "2024-03-11 16:30:00 CST"

# List available timezones
ls /usr/share/zoneinfo/

Python Alternative (for scripting)

from datetime import datetime, timezone

# Current UTC time
utc_now = datetime.now(timezone.utc)
print(utc_now.isoformat())

# Current local time
local_now = datetime.now()
print(local_now.isoformat())

# Unix timestamp
print(int(utc_now.timestamp()))

Notes

• Unix timestamp is always UTC (timezone-independent)
• ISO 8601 format includes timezone offset
• Use timedatectl on Linux systems for system clock info