Assuming I have git installed, does it make
git a command in Windows cmd environment? Why is it not in the output list when I run
help? And same question for
ping command. Thank you
As long as %PATH% lists a directory which contains
git.exe (or git.bat, git.cmd, git.com…), it will be available as a command in both cmd.exe and PowerShell.
The Git for Windows installer asks you whether the directory containing git.exe should be added to %PATH%. You can also do this manually. There are no other steps required to "define" something as a command.
help in Windows' cmd.exe shows a hardcoded list of commands (most of which hasn't changed since MS-DOS era), but does not actually enumerate all commands available in %PATH%. You can ignore this list.