GNU Binutils

The GNU Binutils are a collection of binary tools. The main ones are:

But they also include:

Most of these programs use BFD, the Binary File Descriptor library, to do low-level manipulation. Many of them also use the opcodes library to assemble and disassemble machine instructions.

The binutils have been ported to most major Unix variants as well as Wintel systems, and their main reason for existence is to give the GNU system (and GNU/Linux) the facility to compile and link programs.

Obtaining binutils

The latest release of GNU binutils is 2.16.1. The various NEWS files (binutils, gas, and ld) have details of what has changed in this release.

See the SOFTWARE page for information on obtaining releases of GNU binutils and other GNU software. The current release can be downloaded from

If you plan to do active work on GNU binutils, you can access the development source tree by anonymous CVS:

  cvs -z 9 -d login
  {enter "anoncvs" as the password}
  cvs -z 9 -d co binutils

Alternatively, you can use the cvsweb interface, or the source snapshots, available as bzipped tar files via anonymous FTP from

Bug reports

There is a bug-tracking system at

Mailing lists

There are three binutils mailing lists: (archives)
For reporting bugs. (archives)
For discussing binutils issues.
binutils-cvs (archives)
A read-only mailing list containing the notes from checkins to the binutils CVS repository.

You can use this form to subscribe to the or mailing lists:

Mailing list: Your e-mail address:
Digest version?

To subscribe to the mailing list, see the bug-binutils info page.

You may wish to browse the old mail archives of the gas2 and bfd mailing lists. These were the discussion lists for binutils until May 1999. Please do not send mail to them any longer.


The documentation for binutils 2.16 is available.

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Updated: Last modified: Sun Jun 12 17:00:13 EDT 2005