Question

b. Develop a C Application that implements a multithreaded behaviour of
the CAT command in LINUX using exec calls. (use of built in CAT command not
allowed.

Answer 1

#include<sys/types.h>
#include<sys/stat.h>
#include<stdio.h>
#include<fcntl.h>
main( int argc,char *argv[3] )
{
int fd,i;
char buf[2];
fd=open(argv[1],O_RDONLY,0777);
if(fd==-argc)
{
printf("file open error");
}
else
{
while((i=read(fd,buf,1))>0)
{
printf("%c",buf[0]);
}
close(fd);
}
}

sample input-output

$gcc –o prgcat.out prgcat.c //outputprogram name and c program name for compilation
same of data using cat on a file
student@ubuntu:~$cat > ff
hello
hai
same output using our program on same file
student@ubuntu:~$./prgcat.out ff
hello
hai