---
name: "gensprep"
section: "8"
platform: "linux"
package: "icu"
version: "78.3-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/gensprep"
---

# gensprep(8)

compile StringPrep data from files filtered by filterRFC3454.pl

## NAME

**gensprep** - compile StringPrep data from files filtered by filterRFC3454.pl

## SYNOPSIS

**gensprep** \[ **-h, -?, --help** \] \[ **-v, --verbose** \] \[ **-c, --copyright** \] \[ **-s, --sourcedir** *source* \] \[ **-d, --destdir** *destination* \]

## DESCRIPTION

**gensprep** reads filtered RFC 3454 files and compiles their information into a binary form. The resulting file, **\<name\>.icu**, can then be read directly by ICU, or used by [**pkgdata**(8)](/pkgdata/8.md) for incorporation into a larger archive or library.

The files read by **gensprep** are described in the **FILES** section.

## OPTIONS

- **-h, -?, --help**

  Print help about usage and exit.

- **-v, --verbose**

  Display extra informative messages during execution.

- **-c, --copyright**

  Include a copyright notice into the binary data.

- **-s, --sourcedir** *source*

  Set the source directory to *source*. The default source directory is specified by the environment variable **ICU\_DATA**.

- **-d, --destdir** *destination*

  Set the destination directory to *destination*. The default destination directory is specified by the environment variable **ICU\_DATA**.

## ENVIRONMENT

- **ICU\_DATA**

  Specifies the directory containing ICU data. Defaults to **${prefix}/share/icu/78.3/**. Some tools in ICU depend on the presence of the trailing slash. It is thus important to make sure that it is present if **ICU\_DATA** is set.

## FILES

The following files are read by **gensprep** and are looked for in the *source* /misc for rfc3454\_\*.txt files and in  *source* /unidata for NormalizationCorrections.txt.

- **rfc3453\_A\_1.txt**

  Contains the list of unassigned codepoints in Unicode version 3.2.0....

- **rfc3454\_B\_1.txt**

  Contains the list of code points that are commonly mapped to nothing....

- **rfc3454\_B\_2.txt**

  Contains the list of mappings for casefolding of  code points when Normalization form NFKC is specified....

- **rfc3454\_C\_X.txt**

  Contains the list of code points that are prohibited for IDNA.

- **NormalizationCorrections.txt**

  Contains the list of code points whose normalization has changed since Unicode Version 3.2.0.

## VERSION

78\.3

## COPYRIGHT

Copyright (C) 2000-2002 IBM, Inc. and others.

## SEE ALSO

[**pkgdata**(8)](/pkgdata/8.md)