A real-world use case for referencing a version of a git file came up in practice recently. The suggested solution was to copy a file into git to a folder as the project morphed and evolved over time. I suggested there would be a better way utilizing the power of version control.

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cat-file will work within the git command line to cat a file out at a particular point in time. This command, assuming you have git installed on the machine you want to view this permanent link at, will allow you to do so at any time.