Yep, it considers the current branch (origin/master) as the default if git config --global push.default setting is set to current. This is usually set by default on windows and ios, so simply doing "git push" might work but on some linux distros, this setting isn't set to current but set to nothing instead (which means you'll have to explicitly add the branch).
config --global push.default
Especially, the last time when I'd worked on Ubuntu, simply doing a git push had not worked.
As far as I understood it, the "new" (git 2.0 is from 2014) default is simple.
From the git doc:
When neither the command-line nor the configuration specify what to push,
the default behavior is used, which corresponds to the simple value for push.default:
the current branch is pushed to the corresponding upstream branch, but as a safety measure,
the push is aborted if the upstream branch does not have the same name as the local one.
Of course it may still be that some distro installations either install older versions, or install with a non-default configuration. Somewhat recently having set-up my work laptop on Ubuntu 18.04 I do not recall having to set the push configuration
We're a place where coders share, stay up-to-date and grow their careers.
We strive for transparency and don't collect excess data.