38 lines
1.2 KiB
Markdown
38 lines
1.2 KiB
Markdown
# Rolling Back Configuration Changes {#sec-rollback}
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After running `nixos-rebuild` to switch to a new configuration, you may
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find that the new configuration doesn't work very well. In that case,
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there are several ways to return to a previous configuration.
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First, the GRUB boot manager allows you to boot into any previous
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configuration that hasn't been garbage-collected. These configurations
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can be found under the GRUB submenu "NixOS - All configurations". This
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is especially useful if the new configuration fails to boot. After the
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system has booted, you can make the selected configuration the default
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for subsequent boots:
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```ShellSession
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# /run/current-system/bin/switch-to-configuration boot
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```
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Second, you can switch to the previous configuration in a running
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system:
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```ShellSession
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# nixos-rebuild switch --rollback
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```
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This is equivalent to running:
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```ShellSession
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# /nix/var/nix/profiles/system-N-link/bin/switch-to-configuration switch
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```
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where `N` is the number of the NixOS system configuration. To get a
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list of the available configurations, do:
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```ShellSession
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$ ls -l /nix/var/nix/profiles/system-*-link
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...
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lrwxrwxrwx 1 root root 78 Aug 12 13:54 /nix/var/nix/profiles/system-268-link -> /nix/store/202b...-nixos-13.07pre4932_5a676e4-4be1055
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```
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