---
name: "ndisasm"
section: "1"
platform: "linux"
package: "nasm"
version: "3.02-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/ndisasm"
---

# ndisasm(1)

the Netwide Disassembler, an 80x86 binary file disassembler

## NAME

ndisasm - the Netwide Disassembler, an 80x86 binary file disassembler

## SYNOPSIS

**ndisasm** \[ **-o** origin \] \[ **-s** sync-point \[...\]\] \[ **-a** \| **-i** \] \[ **-b** bits \] \[ **-u** \] \[ **-e** hdrlen \] \[ **-p** vendor \] \[ **-k** offset,length \[...\]\] infile

## DESCRIPTION

The **ndisasm** command generates a disassembly listing of the binary file infile and directs it to stdout.

## OPTIONS

- **-h**

  Causes **ndisasm** to exit immediately, after giving a summary of its invocation options.

**-r**\|**-v**

Causes **ndisasm** to exit immediately, after displaying its version number.

- **-o** *origin*

  Specifies the notional load address for the file. This option causes **ndisasm** to get the addresses it lists down the left hand margin, and the target addresses of PC-relative jumps and calls, right.

- **-s** *sync-point*

  Manually specifies a synchronisation address, such that **ndisasm** will not output any machine instruction which encompasses bytes on both sides of the address. Hence the instruction which starts at that address will be correctly disassembled.

- **-e** *hdrlen*

  Specifies a number of bytes to discard from the beginning of the file before starting disassembly. This does not count towards the calculation of the disassembly offset: the first *disassembled* instruction will be shown starting at the given load address.

- **-k** *offset,length*

  Specifies that *length* bytes, starting from disassembly offset *offset*, should be skipped over without generating any output. The skipped bytes still count towards the calculation of the disassembly offset.

**-a**\|**-i**

Enables automatic (or intelligent) sync mode, in which **ndisasm** will attempt to guess where synchronisation should be performed, by means of examining the target addresses of the relative jumps and calls it disassembles.

- **-b** *bits*

  Specifies 16-, 32- or 64-bit mode. The default is 16-bit mode.

- **-u**

  Specifies 32-bit mode, more compactly than using ‘-b 32’.

- **-p** *vendor*

  Prefers instructions as defined by *vendor* in case of a conflict. Known *vendor* names include **intel**, **amd**, **cyrix**, and **idt**. The default is **intel**.

## RESTRICTIONS

**ndisasm** only disassembles binary files: it has no understanding of the header information present in object or executable files. If you want to disassemble an object file, you should probably be using [**objdump**(1)](/objdump/1.md).

Auto-sync mode won’t necessarily cure all your synchronisation problems: a sync marker can only be placed automatically if a jump or call instruction is found to refer to it *before* **ndisasm** actually disassembles that part of the code. Also, if spurious jumps or calls result from disassembling non-machine-code data, sync markers may get placed in strange places. Feel free to turn auto-sync off and go back to doing it manually if necessary.

## SEE ALSO

[**objdump**(1)](/objdump/1.md)