---
name: "noindex"
section: "1"
platform: "linux"
package: "noweb"
version: "2.13-2"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/noindex"
---

# noindex(1)

build external index for noweb document

## NAME

noindex - build external index for noweb document

## SYNOPSIS

**noindex *basename*\[.tex\]**

## DESCRIPTION

*noindex* looks through  *LaTeX* **.aux** files for identifiers that should go in a *noweb* external index. It sorts all identifiers and writes the results on *basename**.nwi**.*

## NOWEB INDEXING STRATEGIES

A  *noweb* program consists of one or more files. In the simple case, these files are run through *noweave* together, to produce a single *LaTeX* file. *noweave -index* suffices to produce an index and cross-referencing information; neither  *nodefs* nor *noindex* is required.

When a  *noweb* program consists of several source files, it is often better to run each source file through  *noweave* to produce its own  *LaTeX* file, then use *noindex* to produce an external index. This technique has several advantages:

-

  The line numbers in the  *LaTeX* files correspond to the line numbers in the source files, so it is easier to diagnose  *LaTeX* errors.

-

  The *LaTeX* **\\\\includeonly** feature can be used, making it possible to format parts of large programs while retaining complete cross-reference information.

-

  When used with [*make*(1)](/make/1.md), the technique  avoids running  *noweave* over source files that have not changed.

-

  Using the external index places fewer demands on *LaTeX*'s memory, making it read its **.aux** files much more quickly.

The disadvantages are that  *nodefs* and  *noindex* are needed for full cross-referencing and a properly sorted index.

## EXAMPLE

This example assumes a  *noweb* program of three source files: **a.nw ,** **b.nw ,** and **c.nw**. The file **doc.tex** is assumed to contain  *LaTeX* boilerplate, including the commands

-

  \\noweboptions{externalindex}

  ```
  \include{a}
  \include{b}
  \include{c}
  ```

The first sequence of steps is to create a file listing all the identifiers defined anywhere in  **a**, **b**, or  **c**.

-

  nodefs a.nw \> a.defs

  ```
  nodefs b.nw > b.defs
  nodefs c.nw > c.defs
  sort -u a.defs b.defs c.defs | cpif all.defs
  ```

Using *sort -u* and [*cpif*(1)](/cpif/1.md) avoids changing **all.defs** unless the set of identifiers changes. This technique, used in a Makefile, avoids unnecessary rebuilding.

The next series of steps is to create *LaTeX* files with full cross-reference information for all identifiers.

-

  noweave -n -indexfrom all.defs a.nw \> a.tex

  ```
  noweave -n -indexfrom all.defs b.nw > b.tex
  noweave -n -indexfrom all.defs c.nw > c.tex
  ```

The final steps run *LaTeX* once to create **.aux** files, then *noindex* to create the index, then *LaTeX* again to format the complete document.

-

  latex doc

  ```
  noindex doc
  latex doc
  ```

In a Makefile, *noindex* can be run before every invocation of *LaTeX.*

## BUGS

*noindex* is distributed in awk and Icon versions. The awk version is slow and does a poorer job sorting.

There is no comparable machinery to make it possible to use multiple files  with the HTML back end.

## SEE ALSO

[*noweave*(1)](/noweave/1.md), [*nodefs*(1)](/nodefs/1.md), [*cpif*(1)](/cpif/1.md)

## VERSION

This man page is from  *noweb* version 2.12.

## AUTHOR

Norman Ramsey, Tufts University. Internet address **Norman.Ramsey@tufts.edu**.\
 Noweb home page at **http://www.cs.tufts.edu/~nr/noweb**.