22.2 在安装之前运行Guix

为了保持一个合适的工作环境，你会发现在你的本地代码树里测试修改而不用安装它们会很有用。TODO: So that you can distinguish between your “end-user” hat and your “motley” costume.

To that end, all the command-line tools can be used even if you have not run make install. To do that, you first need to have an environment with all the dependencies available (see 从Git构建), and then simply prefix each command with ./pre-inst-env (the pre-inst-env script lives in the top build tree of Guix; it is generated by running ./bootstrap followed by ./configure). As an example, here is how you would build the hello package as defined in your working tree (this assumes guix-daemon is already running on your system; it’s OK if it’s a different version):

$ ./pre-inst-env guix build hello

同样，一个使用 Guix 模块的 Guile 会话的例子：

$ ./pre-inst-env guile -c '(use-modules (guix utils)) (pk (%current-system))'

;;; ("x86_64-linux")

… and for a REPL (see Using Guix Interactively):

$ ./pre-inst-env guile
scheme@(guile-user)> ,use(guix)
scheme@(guile-user)> ,use(gnu)
scheme@(guile-user)> (define snakes
                       (fold-packages
                         (lambda (package lst)
                           (if (string-prefix? "python"
                                               (package-name package))
                               (cons package lst)
                               lst))
                         '()))
scheme@(guile-user)> (length snakes)
$1 = 361

If you are hacking on the daemon and its supporting code or if guix-daemon is not already running on your system, you can launch it straight from the build tree⁴⁰:

$ sudo -E ./pre-inst-env guix-daemon --build-users-group=guixbuild

pre-inst-env脚本设置为此好了所有必要的的环境变量，包括PATH和GUILE_LOAD_PATH。

./pre-inst-env guix pull 不 会更新本地源代码树，它只更新符号链接~/.config/guix/current (see Invoking guix pull)。如果你想更新本地源代码树，请运行git pull。

Sometimes, especially if you have recently updated your repository, running ./pre-inst-env will print a message similar to the following example:

;;; note: source file /home/user/projects/guix/guix/progress.scm
;;;       newer than compiled /home/user/projects/guix/guix/progress.go

This is only a note and you can safely ignore it. You can get rid of the message by running make -j4. Until you do, Guile will run slightly slower because it will interpret the code instead of using prepared Guile object (.go) files.

You can run make automatically as you work using watchexec from the watchexec package. For example, to build again each time you update a package file, run ‘watchexec -w gnu/packages -- make -j4’.