Pub is the package manager for the Dart programming language , containing reusable libraries & packages for Flutter, AngularDart, and general Dart programs. So basically pub is the same as npm or any other package manager but it is specific to dart and flutter.
Read moreWhat does flutter pub upgrade do?
Upgrade is one of the commands of the pub tool. Like dart pub get , dart pub upgrade gets dependencies . The difference is that dart pub upgrade ignores any existing lockfile, so that pub can get the latest versions of all dependencies.
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