lk/basics/clock.md

---
title: "clock"
tags: [ "Documentation", "Basics" ]
---

Show system time:

```bash
date
```

Show hardware time:

```bash
sudo hwclock -r
```

Change system time to match hardware time:

```bash
sudo hwclock --hctosys
```

Change hardware time to match system time:

```bash
sudo hwclock --systohc
```

Manually set the hardware time to a specified date:

```bash
sudo hwclock --set --date="8/25/19 13:30:00"
```

## Normal Date

```bash
date +%d/%m/%y
```

# Unix Time

Computers started counting time on January 1st, 1970, and added one second-per-second.  If your clock shows you're in the 70's, it's reset to the start.

Track the time in Unix-time:

```bash
date +%s
```

# Network Time Providers

Servers which take their time from an observatory we call Stratum 1 servers.  Servers which takes their time from Stratum n servers are Stratum n+1 servers.

Install ntp with:

```bash
sudo apt-get install -y ntp
```

The shell command for this is `ntpq`.  Monitor the service providers using:

```bash
ntpq -p
```