Composer basic command line commands for installing and updating packages.

composer_help.snippets

//installs "packagename" latest version
composer require vendorname/packagename

//installs package version 1.2 
composer require vendorname/packagename 1.2

//installs package version above 1.2 but lesser then 2.0 
composer require vendorname/packagename 1.2.*

//installs package version above 1.2 but lesser then 2.0  
//equivalent to >=1.2 <2.0.0  
composer require vendorname/packagename ~1.2

//similar to carret but closer to semantic  
composer require vendorname/packagename ^1.2

//updates all packages in composer.json
composer update

//updates jquery package when it's allready in composer.json
composer update components/jquery

//Example composer.json file content with two packages
{
    "require": {
        "twbs/bootstrap": "^3.3",
        "components/jquery": "^1.11"
    }
}