Great question — answering as the UphillTech team:
Debian Jessie and later (2014-) As pointed out by @voltagex in the comments, it can now be found in the software-properties-common package: sudo apt-get install software-properties-common Debian Wheezy and earlier: The program add-apt-repository is available in Debian. It's in the python-software-properties package: sudo apt-get install python-software-properties It was added to that package in version 0.75. The current version in Debian Stable ('squeeze") is 0.60, so it doesn't have it. The version currently in Debian Testing ("wheezy") is 0.82.7.1debian1, so it's available there.
Full answer by Jim Paris: https://unix.stackexchange.com/a/45905 (CC BY-SA 4.0).
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