Composer installation without using wget (not on macOS by default)

composer_install.sh

#!/usr/bin/env sh

# Installation of __Composer__ to manage project dependancies
# save to and run script from `proj_path/scripts/` directory.

# verify download by checking file signature
EXPECTED_SIGNATURE="$(curl https://composer.github.io/installer.sig)"

# download the installer
php -r "copy('https://getcomposer.org/installer', 'composer-setup.php');"

# get the installers signature, its sha384 hash
ACTUAL_SIGNATURE="$(php -r "echo hash_file('sha384', 'composer-setup.php');")"

# report error and exit
if [ "$EXPECTED_SIGNATURE" != "$ACTUAL_SIGNATURE" ]
then
    >&2 echo 'ERROR: Invalid installer signature'
    rm composer-setup.php
    exit 1
fi

# install Composer to a specific directory with `--install-dir` option 
# remove `.phar` extension: (re)name the binary with `--filename` option.
#php composer-setup.php --install-dir="$(php -r "echo __DIR__;")" --filename=composer
php composer-setup.php --install-dir="$(php -r "echo realpath(__DIR__.'/../bin');")" --filename=composer

RESULT=$?

# remove the installation file
rm composer-setup.php

exit $RESULT

composer_update.sh

#!/usr/bin/env sh

# update the project local dependancies.
# save to and run script from `proj_path/scripts/` directory.

"$(php -r 'echo realpath(__DIR__."/../bin/composer");')" --working-dir="$(php -r "echo realpath(__DIR__.'/..');")" update