include<stdio.h> include<stdlib.h> include<unistd.h> intmain(intargc,charargv) { if(argc<2){ fprintf(stderr,"faildUsage...\n"); exit(1); } intbuffersize=atoi(argv[1]); charbuf[buffersize]; intn=0; while((n=read(STDIN_FILENO,buf,buffersize))>0){ if(write(STDOUT_FILENO,buf,n)...