PHP error: "The zip extension and unzip command are both missing, skipping."

Not to belabor the point, but if you are working in a Dockerfile, you would solve this particular issue with Composer by installing the unzip utility. Below is an example using the official PHP image to install unzip and the zip PHP extension for good measure.

FROM php:7.4-apache

# Install Composer
COPY --from=composer /usr/bin/composer /usr/bin/composer

# Install unzip utility and libs needed by zip PHP extension 
RUN apt-get update && apt-get install -y \
    zlib1g-dev \
    libzip-dev \
    unzip
RUN docker-php-ext-install zip

This is a helpful GitHub issue where the above is lovingly lifted from.

For servers with PHP 5.6

sudo apt-get install zip unzip php5.6-zip

Depending on your flavour of Linux and PHP version these may vary.

(sudo) yum install zip unzip php-zip
(sudo) apt install zip unzip php-zip

This is a very commonly asked question, you'll be able to find more useful info in the aether by searching <distro> php <version> zip extension.