Why Windows shell (cmd.exe) tends to hang until a key is pressed? [duplicate]

Why would a program that is run from the command line wait for user input (pressing Enter) if it wasn't programmed to do so?

I was using an AWS EC2 instance to run a computationally intensive program that does a few things including reading files, running computations on file contents and creating new files. For each of the tasks the program printed some debug info to stdout.

After going through a couple of steps it seemingly got stuck on a massive computation. The program hadn't advanced for too long and the resource use had dropped from the steady level when starting the step so I hit Enter out of frustration and it immediately proceeded.

• I wasn't prompted for input
• The author reassured me that an input pause wasn't in the source code
• Given the facts a coincidence is very unlikely

Is this a system bug / quirk / feature?

Why could it happen and can I avoid this in the future?

Solution 1:

Windows command prompt (cmd.exe) has a "quick edit" mode which is enabled by default.

With "quick edit" mode enabled, if you click on the command prompt while it is updating, E.g. in the case of running a command such as:

ping www.google.com -t

then updating the output will stop until a key is entered such as Enter in the case of the question.