Removes the references of the specified files to the specified store files. This is done without changing the size of the file by replacing the hash by `eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee`, and should work on compiled executables. This is meant to be used to remove the dependency of the output on inputs that are known to be unnecessary at runtime. Of course, reckless usage will break the patched programs.
To use this, add `removeReferencesTo` to `nativeBuildInputs`.

As `remove-references-to` is an actual executable and not a shell function, it can be used with `find`.
Example removing all references to the compiler in the output:
```nix
{
  postInstall = ''
    find "$out" -type f -exec remove-references-to -t ${stdenv.cc} '{}' +
  '';
}
```

### `runHook` \<hook\> {#fun-runHook}

Execute \<hook\> and the values in the array associated with it. The array's name is determined by removing `Hook` from the end of \<hook\> and appending `Hooks`.

For example, `runHook postHook` would run the hook `postHook` and all of the values contained in the `postHooks` array, if it exists.

### `substitute` \<infile\> \<outfile\> \<subs\> {#fun-substitute}

Performs string substitution on the contents of \<infile\>, writing the result to \<outfile\>. The substitutions in \<subs\> are of the following form:

#### `--replace-fail` \<s1\> \<s2\> {#fun-substitute-replace-fail}

Replace every occurrence of the string \<s1\> by \<s2\>.
Will error if no change is made.

#### `--replace-warn` \<s1\> \<s2\> {#fun-substitute-replace-warn}

Replace every occurrence of the string \<s1\> by \<s2\>.
Will print a warning if no change is made.

#### `--replace-quiet` \<s1\> \<s2\> {#fun-substitute-replace-quiet}

Replace every occurrence of the string \<s1\> by \<s2\>.
Will do nothing if no change can be made.

#### `--subst-var` \<varName\> {#fun-substitute-subst-var}

Replace every occurrence of `@varName@` by the contents of the environment variable \<varName\>. This is useful for generating files from templates, using `@...@` in the template as placeholders.

#### `--subst-var-by` \<varName\> \<s\> {#fun-substitute-subst-var-by}

Replace every occurrence of `@varName@` by the string \<s\>.

Example:

```shell
substitute ./foo.in ./foo.out \
    --replace-fail /usr/bin/bar $bar/bin/bar \
    --replace-fail "a string containing spaces" "some other text" \
    --subst-var someVar
```

### `substituteInPlace` \<multiple files\> \<subs\> {#fun-substituteInPlace}

Like `substitute`, but performs the substitutions in place on the files passed.

### `substituteAll` \<infile\> \<outfile\> {#fun-substituteAll}

Replaces every occurrence of `@varName@`, where \<varName\> is any environment variable, in \<infile\>, writing the result to \<outfile\>. For instance, if \<infile\> has the contents

```bash
#! @bash@/bin/sh
PATH=@coreutils@/bin
echo @foo@
```

and the environment contains `bash=/nix/store/bmwp0q28cf21...-bash-3.2-p39` and `coreutils=/nix/store/68afga4khv0w...-coreutils-6.12`, but does not contain the variable `foo`, then the output will be

```bash
#! /nix/store/bmwp0q28cf21...-bash-3.2-p39/bin/sh
PATH=/nix/store/68afga4khv0w...-coreutils-6.12/bin
echo @foo@
```

That is, no substitution is performed for undefined variables.

Environment variables that start with an uppercase letter or an underscore are filtered out, to prevent global variables (like `HOME`) or private variables (like `__ETC_PROFILE_DONE`) from accidentally getting substituted. The variables also have to be valid bash "names", as defined in the bash manpage (alphanumeric or `_`, must not start with a number).

### `substituteAllInPlace` \<file\> {#fun-substituteAllInPlace}

Like `substituteAll`, but performs the substitutions in place on the file \<file\>.

### `stripHash` \<path\> {#fun-stripHash}

Strips the directory and hash part of a store path, outputting the name part to `stdout`. For example:

```bash
# prints coreutils-8.24
stripHash "/nix/store/9s9r019176g7cvn2nvcw41gsp862y6b4-coreutils-8.24"