Apropos: Difference between revisions

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By default as of NixOS 21.05, <code>apropos</code>, <code>whatis</code> and <code>man -k</code> do not find anything when run, because the man page index cache is not generated.

To ~~generate it manually (and again to update it when new software is installed)~~, ~~run~~:

To build the cache automatically, you can set this in your system configuration:

~~$ sudo mkdir -p /var/~~cache/man~~/nixos~~

{

~~$ sudo mandb~~

documentation.man.cache.enable = true;

}

</syntaxhighlight>

Or in older versions:

{

documentation.man.generateCaches = true;

}

</syntaxhighlight>

This will create an immutable cache in sync with <code>environment.systemPackages</code>. Since it is immutable, the <code>mandb</code> command (see below) will fail.

~~To enable automatically building~~ the ~~immutable~~ cache, ~~you can set in~~ your ~~system configuration~~:

If you are using home-manager, the above will not populate the cache with the programs installed that way, instead add this to your <code>home.nix</code>:

{

~~documentation~~.man.generateCaches = true;

programs.man.generateCaches = true;

}

</syntaxhighlight>

~~Note~~ that ~~this will rebuild~~ the ~~cache every time you change anything in <code>environment~~.~~systemPackages<~~/~~code>~~, ~~and will make the~~ <~~code~~>mandb</~~code~~> ~~command fail~~.

Some programs might set one of these options to true by default, in that case you might still need to set the other to true manually. An example of such a program is [[fish]], which uses it to automatically create completions (see [fish_update_completions](https://fishshell.com/docs/current/cmds/fish_update_completions.html)).

To generate it manually, run:

$ sudo mkdir -p /var/cache/man/nixos

$ sudo mandb

</syntaxhighlight>

This will need to be re-run to update the cache when new software is installed.

[[Category:Configuration]]

@@ Line 1: / Line 1: @@
 By default as of NixOS 21.05, <code>apropos</code>, <code>whatis</code> and <code>man -k</code> do not find anything when run, because the man page index cache is not generated.
-To generate it manually (and again to update it when new software is installed), run:
+To build the cache automatically, you can set this in your system configuration:
-<syntaxhighlight lang="console">
+<syntaxhighlight lang="nix">
-$ sudo mkdir -p /var/cache/man/nixos
+{
-$ sudo mandb
+  documentation.man.cache.enable = true;
+}
+</syntaxhighlight>
+Or in older versions:
+<syntaxhighlight lang="nix">
+{
+  documentation.man.generateCaches = true;
+}
 </syntaxhighlight>
+This will create an immutable cache in sync with <code>environment.systemPackages</code>. Since it is immutable, the <code>mandb</code> command (see below) will fail.
-To enable automatically building the immutable cache, you can set in your system configuration:
+If you are using home-manager, the above will not populate the cache with the programs installed that way, instead add this to your <code>home.nix</code>:
 <syntaxhighlight lang="nix">
 {
-   documentation.man.generateCaches = true;
+   programs.man.generateCaches = true;
 }
 </syntaxhighlight>
-Note that this will rebuild the cache every time you change anything in <code>environment.systemPackages</code>, and will make the <code>mandb</code> command fail.
+Some programs might set one of these options to true by default, in that case you might still need to set the other to true manually. An example of such a program is [[fish]], which uses it to automatically create completions (see [fish_update_completions](https://fishshell.com/docs/current/cmds/fish_update_completions.html)).
+To generate it manually, run:
+<syntaxhighlight lang="console">
+$ sudo mkdir -p /var/cache/man/nixos
+$ sudo mandb
+</syntaxhighlight>
+This will need to be re-run to update the cache when new software is installed.
 [[Category:Configuration]]