How to Generate UNIX Timestamps in Linux

Unix timestamps represent dates and times as a single number – the number of seconds since January 1st, 1970 at 00:00:00 UTC. They are commonly used in programming and systems administration to handle dates and times in a standardized way across platforms.

Here are several methods to generate UNIX timestamps in Linux:

Using the date Command

The date command in Linux can generate UNIX timestamps with the +%s format specifier:

date +%s

This will output the current timestamp.

To generate a timestamp for a specific date:

date -d "2023-03-10 12:00:00" +%s

The -d option parses the provided date/time string and outputs the corresponding timestamp.

You can also generate timestamps in nanoseconds with:

date +%s%N

Using Perl

Perl has a built-in time function that returns the current UNIX timestamp:

#!/usr/bin/perl
print time(); 

Save this as a script, make it executable, and run it to output the timestamp.

Using Python

Similarly, Python has a time module with a time() function:

#!/usr/bin/python3
import time
print(int(time.time()))

The time.time() method returns a float, so convert it to an integer to get a proper UNIX timestamp.

Bash Script

You can also generate timestamps in a Bash script:

#!/bin/bash

timestamp=$(date +%s)
echo $timestamp

The $(date +%s) command substitution will be replaced with the output timestamp value.

Converting Timestamps to Dates

To convert a UNIX timestamp back to a human-readable date, pass it to the date command with the @ option:

date -d @1678414400

This will convert the provided timestamp to a date/time in the configured system timezone.

You can also format the output date string:

date -d @1678414400 +"%Y-%m-%d %H:%M:%S"

So in summary, UNIX timestamps provide a simple way to handle dates/times in scripts and programs. The date command and programming languages make it easy to generate and convert timestamps.