[Software] When should [arch=...] be used in source list?

[xuhdev]

Sometimes I saw this in source list

Code: Select all

deb [arch=amd64] ...

Is the "arch" property really necessary? If so, when should we explicitly specify it?

[dilberts_left_nut]

When you want access to packages for an architecture that is not your default.

[fabien]

To add to what @dilberts_left_nut said,

By default, APT updates /var/lib/apt/lists/ based on the system's configured architectures which are the combined output of dpkg --print-architecture and dpkg --print-foreign-architectures.

If you don't have a foreign architecture on your system, you can still force APT to download files for other architectures. If you have foreign architectures, you can limit the update to the chosen architecture(s).

e.g: [ arch=amd64,i386,armhf ]

If your architecture is amd64, [ arch=i386,armhf ] will force i386 and armhf but amd64 will not be downloaded.
[ arch=amd64 ] is useless if your architecture is amd64 and you don't have foreign architectures (unless specific APT configuration, not the general case).