diff options
Diffstat (limited to 'doc/manual/src/expressions/builder-syntax.md')
| -rw-r--r-- | doc/manual/src/expressions/builder-syntax.md | 20 |
1 files changed, 10 insertions, 10 deletions
diff --git a/doc/manual/src/expressions/builder-syntax.md b/doc/manual/src/expressions/builder-syntax.md index c92acf106..916159d40 100644 --- a/doc/manual/src/expressions/builder-syntax.md +++ b/doc/manual/src/expressions/builder-syntax.md @@ -19,29 +19,29 @@ what a builder does. It performs the following steps: - When Nix runs a builder, it initially completely clears the environment (except for the attributes declared in the derivation). - For instance, the PATH variable is empty\[1\]. This is done to + For instance, the `PATH` variable is empty\[1\]. This is done to prevent undeclared inputs from being used in the build process. If - for example the PATH contained `/usr/bin`, then you might + for example the `PATH` contained `/usr/bin`, then you might accidentally use `/usr/bin/gcc`. So the first step is to set up the environment. This is done by calling the `setup` script of the standard environment. The - environment variable stdenv points to the location of the standard + environment variable `stdenv` points to the location of the standard environment being used. (It wasn't specified explicitly as an attribute in [???](#ex-hello-nix), but `mkDerivation` adds it automatically.) - Since Hello needs Perl, we have to make sure that Perl is in the - PATH. The perl environment variable points to the location of the - Perl package (since it was passed in as an attribute to the + `PATH`. The `perl` environment variable points to the location of + the Perl package (since it was passed in as an attribute to the derivation), so `$perl/bin` is the directory containing the Perl interpreter. - Now we have to unpack the sources. The `src` attribute was bound to the result of fetching the Hello source tarball from the network, so - the src environment variable points to the location in the Nix store - to which the tarball was downloaded. After unpacking, we `cd` to the - resulting source directory. + the `src` environment variable points to the location in the Nix + store to which the tarball was downloaded. After unpacking, we `cd` + to the resulting source directory. The whole build is performed in a temporary directory created in `/tmp`, by the way. This directory is removed after the builder @@ -55,13 +55,13 @@ what a builder does. It performs the following steps: separate location in the Nix store, for instance `/nix/store/9a54ba97fb71b65fda531012d0443ce2-hello-2.1.1`. Nix computes this path by cryptographically hashing all attributes of - the derivation. The path is passed to the builder through the out + the derivation. The path is passed to the builder through the `out` environment variable. So here we give `configure` the parameter `--prefix=$out` to cause Hello to be installed in the expected location. - Finally we build Hello (`make`) and install it into the location - specified by out (`make install`). + specified by `out` (`make install`). If you are wondering about the absence of error checking on the result of various commands called in the builder: this is because the shell |