运行以下命令：
curl -sS https://getcomposer.org/installer | php
我收到这条消息：
#！/usr/bin/env php 计算机上的某些设置使 Composer 无法正常工作。 请确保修复下面列出的问题，然后再次运行此脚本：
缺少法尔扩展名。 安装它或重新编译 php 而不使用 --disable-phar
缺少openssl扩展，这意味着安全的HTTPS传输是不可能的。 如果可能的话，你应该启用它或使用 --with-openssl 重新编译 php
我安装了 php：
sudo zypper in php5 php5-mcrypt php5-json php5-cli
和卷曲。像其他命令一样证明作曲家什么都没有
安装 openssl 扩展
sudo zypper in php5-openssl
或同时安装两者
sudo zypper in php5-openssl php5-phar
在 openSUSE Leap 42.1 上测试：
# zypper in php5-openssl php5-phar
。
# php -r "copy('https://getcomposer.org/installer', 'composer-setup.php');"
# php -r "if (hash_file('SHA384', 'composer-setup.php') === 'e115a8dc7871f15d853148a7fbac7da27d6c0030b848d9b3dc09e2a0388afed865e6a3d6b3c0fad45c48e2b5fc1196ae') { echo 'Installer verified'; } else { echo 'Installer corrupt'; unlink('composer-setup.php'); } echo PHP_EOL;"
Installer verified
# php composer-setup.php --install-dir=/bin --filename=composer
All settings correct for using Composer
Downloading 1.2.1...
Composer successfully installed to: /bin/composer
Use it: php /bin/composer
# php -r "unlink('composer-setup.php');"
# composer
______
/ ____/___ ____ ___ ____ ____ ________ _____
/ / / __ / __ `__ / __ / __ / ___/ _ / ___/
/ /___/ /_/ / / / / / / /_/ / /_/ (__ ) __/ /
____/____/_/ /_/ /_/ .___/____/____/___/_/
/_/
Composer version 1.2.1 2016-09-12 11:27:19
Usage:
command [options] [arguments]
Options:
-h, --help Display this help message
-q, --quiet Do not output any message
-V, --version Display this application version
--ansi Force ANSI output
--no-ansi Disable ANSI output
-n, --no-interaction Do not ask any interactive question
--profile Display timing and memory usage information
--no-plugins Whether to disable plugins.
-d, --working-dir=WORKING-DIR If specified, use the given directory as working directory.
-v|vv|vvv, --verbose Increase the verbosity of messages: 1 for normal output, 2 for more verbose output and 3 for debug
Available commands:
about Short information about Composer
archive Create an archive of this composer package
browse Opens the package's repository URL or homepage in your browser.
clear-cache Clears composer's internal package cache.
clearcache Clears composer's internal package cache.
config Set config options
create-project Create new project from a package into given directory.
depends Shows which packages cause the given package to be installed
diagnose Diagnoses the system to identify common errors.
dump-autoload Dumps the autoloader
dumpautoload Dumps the autoloader
exec Execute a vendored binary/script
global Allows running commands in the global composer dir ($COMPOSER_HOME).
help Displays help for a command
home Opens the package's repository URL or homepage in your browser.
info Show information about packages
init Creates a basic composer.json file in current directory.
install Installs the project dependencies from the composer.lock file if present, or falls back on the composer.json.
licenses Show information about licenses of dependencies
list Lists commands
outdated Shows a list of installed packages that have updates available, including their latest version.
prohibits Shows which packages prevent the given package from being installed
remove Removes a package from the require or require-dev
require Adds required packages to your composer.json and installs them
run-script Run the scripts defined in composer.json.
search Search for packages
self-update Updates composer.phar to the latest version.
selfupdate Updates composer.phar to the latest version.
show Show information about packages
status Show a list of locally modified packages
suggests Show package suggestions
update Updates your dependencies to the latest version according to composer.json, and updates the composer.lock file.
validate Validates a composer.json and composer.lock
why Shows which packages cause the given package to be installed
why-not Shows which packages prevent the given package from being installed
参考资料：@dougis的回答和 https://getcomposer.org/download/