Read a large file Post: 303014558

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LEARN ABOUT V7

ppmtopgm

ppmtopgm(1)						      General Commands Manual						       ppmtopgm(1)

NAME

       ppmtopgm - convert a portable pixmap into a portable graymap

SYNOPSIS

       ppmtopgm [ppmfile]

DESCRIPTION

       Reads  a  portable  pixmap  as  input.  Produces a portable graymap as output.  The output is a "black and white" rendering of the original
       image, as in a black and white photograph.  The quantization formula used is .299 r + .587 g + .114 b.

       Note that although there is a pgmtoppm program, it is not necessary for simple conversions from pgm to ppm , because any  ppm  program  can
       read  pgm  (and	pbm  ) files automatically.  pgmtoppm is for colorizing a pgm file.  Also, see ppmtorgb3 for a different way of converting
       color to gray.  And ppmdist generates a grayscale image from a color image, but in a way that makes it easy to differentiate  the  original
       colors, not necessarily a way that looks like a black and white photograph.

QUOTE

       Cold-hearted orb that rules the night
       Removes the colors from our sight
       Red is gray, and yellow white
       But we decide which is right
       And which is a quantization error.

SEE ALSO

       pgmtoppm(1),ppmtorgb3(1),rgb3toppm(1),ppmdist(1),ppm(5),pgm(5)

AUTHOR

       Copyright (C) 1989 by Jef Poskanzer.

								   10 April 2000						       ppmtopgm(1)

10 More Discussions You Might Find Interesting

1. Filesystems, Disks and Memory

Strange difference in file size when copying LARGE file..

Discussion started by: 0ktalmagik

2. Shell Programming and Scripting

Split large file and add header and footer to each file

Discussion started by: ashish4422

3. UNIX for Advanced & Expert Users

Shell script failing to read large Xml record-urgent critical help

Discussion started by: aixjadoo

4. Programming

Read/Write a fairly large amount of data to a file as fast as possible

Discussion started by: emitrax