https://docs.python.org/dev/library/subprocess.html#subprocess-replacements documentation suggests to replace os.popen(cmd, "w") with Popen(cmd, stdin=PIPE): without shell=True. My problem is that the replacement does change the behavior if the command does not exist.

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I would like to avoid a shell (shell=True) to avoid any risk of shell injection vulnerability, but also to avoid bugs caused by the usage of a shell.

For example, "*" is a joker character. "*.py" is expanded to the list of filenames ending with ".py", or left unchanged if there is no file with a name ending with ".py". It's surprising if you are not used to a shell, and you expect "*" to be passed to the final command.

There are other weird cases with a shell, like bpo-26124 "shlex.quote and pipes.quote do not quote shell keywords".

See bpo-42641 "Deprecate os.popen() function" for other examples.