---
name: "sgitopnm"
section: "1"
platform: "linux"
package: "netpbm"
version: "10.86.51-2"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/sgitopnm"
---

# sgitopnm(1)

convert a SGI image file to PNM

## NAME

sgitopnm - convert a SGI image file to PNM

## SYNOPSIS

**sgitopnm**

\[**-verbose**\]

\[**-channel** *c*\]

\[*SgiFileName*\]

## DESCRIPTION

This program is part of **Netpbm**(1) .

**sgitopnm** reads an SGI image file as input and produces a PGM image for a 2-dimensional (1- or 2-channel) input file, and a PPM image for a 3-dimensional (3 or more channels) input file.

Alternatively, the program produces a PGM image of any one of the channels in the input file.

Before Netpbm 10.67 (June 2014), **sgitopnm** does not work on 2-channel SGI images.  It fails if you try.

If you don't specify the *SgiFileName* argument, input is from Standard Input.

Before Netpbm 10.67 (June 2014), **sgitopnm** requires its input to be a seekable file, so for example you can't feed it from a pipe.

## OPTIONS

In addition to the options common to all programs based on libnetpbm (most notably **-quiet**, see \
  Common Options ⟨index.html#commonoptions⟩ ), **sgitopnm** recognizes the following command line options:

- **-verbose**

  Give some information about the SGI image file.

- **-channel** *n*

  Extract channel *n* of the image as a PGM image.

  Without this option, **sgitopnm** extracts the first 3 channels as a PPM image or, if the input has 1 or 2 channels, extracts the first channel as a PGM image.

  A 2-channel image is grayscale plus transparency, so you can get the transparency information with **-channel=2**.  You could then combine them into a PAM image of tuple type GRAYSCALE\_ALPHA with **pamstack**.

## REFERENCES

The SGI image format specification version 1.0 is at ftp://ftp.sgi.com/graphics/grafica/sgiimage.html .

There is an example SGI file at  https://github.com/ZaaLabs/ZaaIL-TestImages/tree/master/SGI .

## SEE ALSO

**pnm**(1) , **pam**(1) , [**pnmtosgi**(1)](/pnmtosgi/1.md) , [**pamstack**(1)](/pamstack/1.md)

## AUTHOR

Copyright (C) 1994 by Ingo Wilken ( *Ingo.Wilken@informatik.uni-oldenburg.de*)

## DOCUMENT SOURCE

This manual page was generated by the Netpbm tool 'makeman' from HTML source.  The master documentation is at

-

  **http://netpbm.sourceforge.net/doc/sgitopnm.html**