咨询‘python -’命令的作用、Poetry安装命令的功能及Bash中‘-’的术语名称

When you run python -, you’re telling the Python interpreter to read and execute code from standard input (stdin) instead of loading code from a local .py file. This is handy for running code on the fly—either by typing it directly into the terminal, or by piping output from another command into Python to execute immediately.

Let’s unpack this one-liner step by step:

curl -sSL https://raw.githubusercontent.com/python-poetry/poetry/master/install-poetry.py | python -

• curl -sSL [URL]: This fetches the raw Poetry installation script from the GitHub repository. Here’s what each flag does:
  • -s: Runs curl in "silent" mode, hiding progress bars and non-essential output.
  • -S: Ensures curl still shows error messages if the request fails (so you don’t miss issues like broken links or network errors).
  • -L: Follows any HTTP redirects automatically, in case the original URL points to another location.
• The pipe |: Takes the output of the curl command (the full text of the install script) and passes it directly to python -.
• python -: Executes the script content coming from stdin (via the pipe) just like it would a local file.

The end result is a quick way to install Poetry without needing to download the script file to your computer first.

In this context, the - is a well-established POSIX convention that acts as a placeholder for standard input (stdin). Most command-line tools recognize this symbol to mean: "Don’t look for a file path here—read input from the stream coming in via stdin instead".

You might hear it referred to as a "dash argument" or "stdin placeholder", but the core idea is that it’s a universal shorthand for directing a command to use input from pipes, redirects, or manual user entry instead of a file.

内容的提问来源于stack exchange，提问作者Jwan622