多年来，我一直认为apt update和的结果apt-get update是相同的。顺便说一句 - 是的，我知道apt并且apt-get不完全相同。
我最近注意到，一旦我apt update在我的 Ubuntu 机器上运行，它会检查 13 个源，但apt-get update只检查 7 个源。/etc/apt/sources.list此外，下面列出了总共 7 个更新源/etc/apt/sources.list.d/*
我在网上找不到任何有关此的信息。周围有人能给我解释一下吗？
***编辑这是我的 Mint 盒子的类似输出。它表现出相同的行为。我可能错过了一些东西，但不确定它是什么。
pcko@MBP12:~$ sudo apt update
[sudo] password for pcko:
Ign:1 http://packages.linuxmint.com una InRelease
Hit:2 http://packages.linuxmint.com una Release
Hit:4 http://packages.microsoft.com/repos/code stable InRelease
Hit:5 http://archive.canonical.com/ubuntu focal InRelease
Hit:6 http://archive.ubuntu.com/ubuntu focal InRelease
Get:7 http://archive.ubuntu.com/ubuntu focal-updates InRelease [114 kB]
Get:8 http://archive.ubuntu.com/ubuntu focal-backports InRelease [108 kB]
Get:9 http://security.ubuntu.com/ubuntu focal-security InRelease [114 kB]
Get:10 http://archive.ubuntu.com/ubuntu focal-updates/main amd64 Packages [1,745 kB]
Get:11 http://archive.ubuntu.com/ubuntu focal-updates/main amd64 DEP-11 Metadata [277 kB]
Get:12 http://archive.ubuntu.com/ubuntu focal-updates/universe amd64 Packages [918 kB]
Get:13 http://security.ubuntu.com/ubuntu focal-security/main amd64 DEP-11 Metadata [40.6 kB]
Get:14 http://archive.ubuntu.com/ubuntu focal-updates/universe amd64 DEP-11 Metadata [390 kB]
Get:15 http://security.ubuntu.com/ubuntu focal-security/universe amd64 DEP-11 Metadata [66.3 kB]
Get:16 http://archive.ubuntu.com/ubuntu focal-updates/multiverse amd64 DEP-11 Metadata [940 B]
Get:17 http://archive.ubuntu.com/ubuntu focal-backports/main amd64 DEP-11 Metadata [7,980 B]
Get:18 http://archive.ubuntu.com/ubuntu focal-backports/universe amd64 DEP-11 Metadata [30.8 kB]
Get:19 http://security.ubuntu.com/ubuntu focal-security/multiverse amd64 DEP-11 Metadata [2,464 B]
Fetched 3,816 kB in 2s (1,574 kB/s)
Reading package lists... Done
Building dependency tree
Reading state information... Done
211 packages can be upgraded. Run 'apt list --upgradable' to see them.
pcko@MBP12:~$ sudo apt-get update
Ign:1 http://packages.linuxmint.com una InRelease
Hit:2 http://packages.linuxmint.com una Release
Hit:3 http://packages.microsoft.com/repos/code stable InRelease
Hit:4 http://archive.ubuntu.com/ubuntu focal InRelease
Hit:6 http://security.ubuntu.com/ubuntu focal-security InRelease
Hit:7 http://archive.canonical.com/ubuntu focal InRelease
Hit:8 http://archive.ubuntu.com/ubuntu focal-updates InRelease
Hit:9 http://archive.ubuntu.com/ubuntu focal-backports InRelease
Reading package lists... Done
pcko@MBP12:~$ cd /etc/apt
pcko@MBP12:/etc/apt$ ls
apt.conf.d auth.conf.d preferences.d sources.list sources.list.d trusted.gpg.d
pcko@MBP12:/etc/apt$ cat sources.list
#deb cdrom:[Linux Mint 20.3 _Una_ - Release amd64 20220104]/ focal contrib main
# This system was installed using small removable media
# (e.g. netinst, live or single CD). The matching "deb cdrom"
# entries were disabled at the end of the installation process.
# For information about how to configure apt package sources,
# see the sources.list(5) manual.
pcko@MBP12:/etc/apt$ cd sources.list.d/
pcko@MBP12:/etc/apt/sources.list.d$ ls
official-package-repositories.list vscode.list
pcko@MBP12:/etc/apt/sources.list.d$ cat official-package-repositories.list
# Do not edit this file manually, use Software Sources instead.
deb http://packages.linuxmint.com una main upstream import backport #id:linuxmint_main
deb http://archive.ubuntu.com/ubuntu focal main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu focal-updates main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu focal-backports main restricted universe multiverse
deb http://security.ubuntu.com/ubuntu/ focal-security main restricted universe multiverse
deb http://archive.canonical.com/ubuntu/ focal partner
pcko@MBP12:/etc/apt/sources.list.d$ cat vscode.list
### THIS FILE IS AUTOMATICALLY CONFIGURED ###
# You may comment out this entry, but any other modifications may be lost.
deb [arch=amd64,arm64,armhf] http://packages.microsoft.com/repos/code stable main
答案1
经过进一步研究，我同意@muru的评论是准确的：
请注意，如果 apt 发现现有信息是最新的，则不会进行完整检查（我不记得检查的确切机制，可能是标头提供的时间戳）。无论如何，如果您多次尝试此操作，但更改顺序，您会发现通常运行的第一个命令会下载更多文件，无论是哪个文件。