A quicky for my archives: Convert decimal to hex in Bash, and hexadecimal to decimal. 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 prompt…

Convert decimal to hex in bash

You can use the Linux bash shell to convert decimal values to hexadecimal, and vice versa. For example:

Decimal to hexadecimal in bash

printf '%x\n' 26560
67c0

Hexadecimal to decimal

echo $((0x000067c0))
26560
echo $((0x67c0))
26560
printf '%d\n' 0x67c0
26560

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'.

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