Some handy shell scripts:

1) You  can open headerless raw images in xv directly using a simple 1
line shell script. Of course you would need to know the image
dimensions:

create a file named: xh 

containing the following one line code:

echo $1 $2 $3 255 | cat - $4 | xv -

Change file permission to make it executable by the shell:

chmod 755 xh;

To view a grayscale raw image file (8 bit raster scan) which has no header,
type the following at the command prompt:

xh P5 column_size row_size file_name

for raw color image files (3*8 bit raster scan) use P6 instead of P5.

2) Again, you can easily add header information to a headerless raw image
without having to open an editor or run C code. Simply create a file named:
addhdr with the following 3 line code:

echo $1 $2 $3 255 > $4.header
cat $4 >> $4.header
\mv $4.header $4

and at the command prompt type:

addhdr P5 column_size row_size file_name

WARNING: if there already exists a file called: file_name.header, it
gets deleted.

--------------------------------------------------------------------------------
% Matlab function to read in raw images:
% In Matlab, the % symbol denotes a commented line

function Image = read(filename,rows,columns)

% Usage: Image = read(filename,rowsize,colsize);
%
% returns an integer array of intensity values of the image in 
% the specified file where the image is assumed to be saved in 
% 8 bit grayscale raw format with its xv header removed.
% The read image is displayed for verification

fid = fopen(filename,'r');
Image = fread(fid,[columns,rows],'uchar');
fclose(fid);
Image = Image';            % Matlab reads data in column order
%imshow(Image,[0,255]);     % Display image 

--------------------------------------------------------------------------------

/* Interesting macro for rounding floats to integers */

#define round(x) ((int)((int)x + (int)(2*(x-(int)x))))


/*
 C  code for representing, reading, and writing image data using 2-D arrays 
*/

  int **array, i,j, Rsize, Csize;

/* 
i indexes rows, j indexes columns, Rsize = number of rows,
Csize = number of columns 
*/
 
/* allocate memory for 2-D array */

  array = (int **)malloc(Rsize*sizeof(int *));
  for(i=0;i<Rsize;i++)
     array[i] = (int *)malloc(Csize*sizeof(int));

/* Open files from which to read and write image data*/

  FILE *image_file, *out_file;

  image_file = fopen("file_name_of_the_image_data_file_to_be_read","r");
  out_file = fopen("file_name_of_the_output_image_data_file_to_be_written","w");

/* Read image into the 2-D array */

  for(i=0; i<Rsize; i++)
    for(j=0; j<Csize; j++)
      {
        array[i][j]=getc(image_file);
      }

/* Code for manipulating images.... */
 
/* Write image to output file */

  for(i=0; i<Rsize; i++)
    for(j=0; j<Csize; j++)
      {
        putc(array[i][j],out_file);
      }

/* free allocated memory before quitting program */

  for(i=0;i<Rsize;i++)
    free(array[i]);
  free(array);

/* Close all opened files before quitting */

  fclose(image_file);
  fclose(out_file);	
--------------------------------------------------------------------------------