Verify and install composer from bash command line

install.sh

#!/bin/bash
# Verify and install composer from https://getcomposer.org/installer

me=`basename "$0"`

if [[ $# -eq 0 ]] ; then
    echo "Usage: $me <hash>"
    echo 'where <hash> is the hash value of the installer to verify'
    exit 1
fi

hash=$1

php -r "readfile('https://getcomposer.org/installer');" > composer-setup.php
php -r "if (hash('SHA384', file_get_contents('composer-setup.php')) === '$hash') { echo 'Installer verified'; } else { echo 'Installer corrupt'; unlink('composer-setup.php'); } echo PHP_EOL;"

if [ -f composer-setup.php ]; then
    php composer-setup.php
    php -r "unlink('composer-setup.php');"
fi

You need to pass the hash value from the command line to verify the composer installer. The hash code can be found here.