Can't send input to running program in Sublime Text

Sublime Text on its own cannot handle input via raw_input() (Python 2) or input() (Python 3). The same is true of other languages as well - Ruby's gets, Java's Scanner class, Node's readline class, scanf in C, cin in C++, etc. One short-term solution is to get Package Control if you don't already have it, then install SublimeREPL. It allows you to transfer or run part or all of your code through the running REPL. It may require some configuration of the Main.sublime-menu files to get your preferred interpreter to run properly.

If the code you're running doesn't play well with SublimeREPL (for instance, you're using C/C++/Java/etc. and need to compile code before it runs), or you just want to run it independently of Sublime, you'll need to make your own build system. Save the following as Packages/User/Python_cmd.sublime-build:

Windows

{
    "cmd": ["start", "cmd", "/k", "c:/python38/python.exe", "$file"],
    "selector": "source.python",
    "shell": true,
    "working_dir": "$file_dir",
    "env": {"PYTHONIOENCODING": "utf-8"}
}

changing the path to your Python executable as appropriate. Then, go to Tools -> Build System and select Python_cmd, and when you hit CtrlB to build, a new cmd window will open up with your file running. The /k option returns to the command prompt, without closing the window, after your program is done running so you can examine output, tracebacks, etc.

Please note that this build system is Windows-specific, as macOS and Linux do not have cmd. Build systems for those platforms are below.

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If you are running OS X/macOS, the following build system will open your program in a new instance of Terminal. Save it as Packages/User/Python_Terminal.sublime-build. In my testing on macOS 10.15, the Terminal window didn't always come to the top when activated, so if you may need to look for it behind other windows.

macOS

{
    "shell_cmd": "osascript -e 'tell app \"Terminal\" to do script \"cd $file_path && python3 -u $file\"'",
    "working_dir": "$file_path",
    "selector": "source.python",
    "env": {"PYTHONIOENCODING": "utf-8"}
}

You may need to specify the path to your Python executable if it's not on your $PATH.

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And finally, here is a build system for Linux. It was tested on Ubuntu, so if you use another distribution you'll need to ensure that gnome-terminal is installed. Save it as Packages/User/Python_shell.sublime-build. Once the program has finished running, hit any key to close the window.

Linux

{
    "shell_cmd": "gnome-terminal --working-directory=$file_path -- bash -c 'python3 -u \"$file\" && read -n 1 -s -r'",
    "working_dir": "$file_path",
    "selector": "source.python",
    "env": {"PYTHONIOENCODING": "utf-8"}
}

For reference, the Packages directory is the one opened when selecting Preferences → Browse Packages…:

• Linux: ~/.config/sublime-text-3/Packages
• OS X: ~/Library/Application Support/Sublime Text 3/Packages
• Windows Regular Install: C:\Users\YourUserName\AppData\Roaming\Sublime Text 3\Packages
• Windows Portable Install: InstallationFolder\Sublime Text 3\Data\Packages

I have only tested these build systems with Python, but they should work fine for any language. When modifying, just make sure that all the single and double quotes match up – you'll get errors or unexpected behavior if they don't.