Convert decimal to hex in Bash, hexadecimal to decimal and dates to Unix timestamp

A quicky for my archives, learn how to convert decimal to hex and hexadecimal to decimal, in Bash…

In mathematics and computing, hexadecimal (also base 16, or hex) is a positional numeral system with a radix, or base, of 16. It uses sixteen distinct symbols, most often the symbols 0-9 to represent values zero to nine, and A, B, C, D, E, F (or alternatively a-f) to represent values ten to fifteen. If you want to convert hexadecimal values to decimal and decimal values to hexadecimal, here’s how. All on the bash command-prompt…

For example:

Decimal to hexadecimal in bash

Convert decimal to hexadecimal in Bash:

printf '%x\n' 26560
67c0

Hexadecimal to decimal

Convert hexadecimal to decimal in Bash:

echo $((0x000067c0))
26560

echo $((0x67c0))
26560

printf '%d\n' 0x67c0
26560

Bash function to generate a random alphanumeric string

Convert Unix timestamps to dates in Bash

How to convert Unix timestamps to dates in Bash is a little irrelevant in a post on converting decimal to hex in Bash, but it’s still converting something in Bash 🙂 .

Suppose you have an Unix timestamp that you want to convert to a date, here is how with two one liners:

date -d @timestamp

date -d @($date -u +timestamp)

And vice versa, convert a date to an Unix timestamp:

date -d '04/05/2017 11:13:00' +"%s"

The date string is too complex to be documented in the man page, so it is described in info: info '(coreutils) date invocation'.