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Full Discussion: read and write stdin/stdout in unix
Top Forums Programming read and write stdin/stdout in unix Post 302414793 by MrUser on Wednesday 21st of April 2010 03:31:08 AM
Old 04-21-2010
read and write stdin/stdout in unix
Hi,
i am using the below program to read from the standard input or to write to standard out put.

i know that using highlevel functions this can be done better than what i have done here.

i just want to know is there any other method by which i find the exact number of characters ( this will vary in each iteration ) , and write that to STDOUT.

this process i want to terminate with a press of "q".

does read syscall stores the null at the end of string, i have not found that in debug mode.

below is the sample code but its has got the problem of reading and writing garbages.


Code:
#include<unistd.h>
#include<sys/types.h>
#include<sys/stat.h>
#include<fcntl.h>
#include <stdio.h>
#include<string.h>

int main( void )
{
        char buf[20];

        while( 1 )
        {
                       read(STDIN_FILENO , buf ,  sizeof( buf ));
                       write(STDOUT_FILENO, buf , strlen( buf ));

                if(!strcmp(buf,"q\n"))
                        break;
        }

        return 0;
}

 

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LEARN ABOUT MOJAVE

git-hash-object

GIT-HASH-OBJECT(1)                                                  Git Manual                                                  GIT-HASH-OBJECT(1)

NAME

       git-hash-object - Compute object ID and optionally creates a blob from a file

SYNOPSIS

       git hash-object [-t <type>] [-w] [--path=<file>|--no-filters] [--stdin [--literally]] [--] <file>...
       git hash-object [-t <type>] [-w] --stdin-paths [--no-filters]

DESCRIPTION

       Computes the object ID value for an object with specified type with the contents of the named file (which can be outside of the work tree),
       and optionally writes the resulting object into the object database. Reports its object ID to its standard output. This is used by git
       cvsimport to update the index without modifying files in the work tree. When <type> is not specified, it defaults to "blob".

OPTIONS

       -t <type>
           Specify the type (default: "blob").

       -w
           Actually write the object into the object database.

       --stdin
           Read the object from standard input instead of from a file.

       --stdin-paths
           Read file names from the standard input, one per line, instead of from the command-line.

       --path
           Hash object as it were located at the given path. The location of file does not directly influence on the hash value, but path is used
           to determine what Git filters should be applied to the object before it can be placed to the object database, and, as result of
           applying filters, the actual blob put into the object database may differ from the given file. This option is mainly useful for hashing
           temporary files located outside of the working directory or files read from stdin.

       --no-filters
           Hash the contents as is, ignoring any input filter that would have been chosen by the attributes mechanism, including the end-of-line
           conversion. If the file is read from standard input then this is always implied, unless the --path option is given.

       --literally
           Allow --stdin to hash any garbage into a loose object which might not otherwise pass standard object parsing or git-fsck checks. Useful
           for stress-testing Git itself or reproducing characteristics of corrupt or bogus objects encountered in the wild.

GIT

       Part of the git(1) suite

Git 2.17.1                                                          10/05/2018                                                  GIT-HASH-OBJECT(1)
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