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Full Discussion: [Quick question]Problem with execl and GREP
Top Forums UNIX for Dummies Questions & Answers [Quick question]Problem with execl and GREP Post 302694959 by pfpietro on Friday 31st of August 2012 07:22:12 PM
Old 08-31-2012
[Quick question]Problem with execl and GREP
Guys, I have the following code
Code:
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/wait.h>
#include <unistd.h>

void read2();
main(int argc, char** argv)
{
int pid,status;
    pid=fork();
    if ( pid == 0 )
    {
        read2(argv[1], argv[2]);
        exit(0);    
    }
    else
    wait(&status);
}

void read2(char * file, char * stringa)
{
    printf("%s, %s\n",file, stringa);
    execl("grep", "grep", "-c", stringa, file, (char *)0);
        
}

Why I don't see any outputs on the screen when I run my program ?
usying any .txt file I should get on stdout ( screen ) the number of lines that "stringa" shows up. But I don't.

What am I doing wrong ? A friend of mine tryied in his computer and it worked. Why it doesn't work in mine ?
 

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LEARN ABOUT OPENSOLARIS

ppmtosixel

ppmtosixel(1)                                                 General Commands Manual                                                ppmtosixel(1)

NAME

       ppmtosixel - convert a portable pixmap into DEC sixel format

SYNOPSIS

       ppmtosixel [-raw] [-margin] [ppmfile]

DESCRIPTION

       Reads  a  portable  pixmap  as input.  Produces sixel commands (SIX) as output.  The output is formatted for color printing, e.g. for a DEC
       LJ250 color inkjet printer.

       If RGB values from the PPM file do not have maxval=100, the RGB values are rescaled.  A printer control header and a color assignment table
       begin the SIX file.  Image data is written in a compressed format by default.  A printer control footer ends the image file.

OPTIONS

       -raw   If  specified,  each  pixel  will  be explicitly described in the image file.  If -raw is not specified, output will default to com-
              pressed format in which identical adjacent pixels are replaced by "repeat pixel" commands.  A raw file is often an order  of  magni-
              tude larger than a compressed file and prints much slower.

       -margin
              If  -margin  is not specified, the image will be start at the left margin (of the window, paper, or whatever).  If -margin is speci-
              fied, a 1.5 inch left margin will offset the image.

PRINTING

       Generally, sixel files must reach the printer unfiltered.  Use the lpr -x option or cat filename > /dev/tty0?.

BUGS

       Upon rescaling, truncation of the least significant bits of RGB values may result in poor color conversion.  If the original PPM maxval was
       greater  than  100,  rescaling  also reduces the image depth.  While the actual RGB values from the ppm file are more or less retained, the
       color palette of the LJ250 may not match the colors on your screen.  This seems to be a printer limitation.

SEE ALSO

       ppm(5)

AUTHOR

       Copyright (C) 1991 by Rick Vinci.

                                                                   26 April 1991                                                     ppmtosixel(1)
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