1(a)Aim:A Program for display unix environment variablesBranch:III year CSE*********************************************************************************/#includemain(argc,argv,envp)int argc;char *argv;char *envp[];{int i;for(i=0;envp[i]!=(char *)0;i++)printf("%s",envp[i]);}

/**************************************************************************** outputaits@ubuntu:~$ vi display.caits@ubuntu:~$ cc display.caits@ubuntu:~$ ./a.outSSH_AGENT_PID=1405GPG_AGENT_INFO=/tmp/keyring-HrR3dS/gpg:0:1TERM=xtermSHELL=/bin/bashXDG_SESSION_COOKIE=9f469d6cab42bfff79cd4a3d00000007-1393318574.605405-1361169380WINDOWID=54525958GNOME_KEYRING_CONTROL=/tmp/keyring-HrR3dSUSER=aitsLS_COLORS=rs=0:di=01;34:ln=01;36:mh=00:pi=40;33:so=01;35:do=01;35:bd=40;33;01:cd=40;33;01:or=40;31;01:su=37;41:sg=30;43:ca=30;41:tw=30;42:ow=34;42:st=37;44:ex=01;32:*.tar=01;31:*.tgz=01;31:*.arj=01;31:*.taz=01;31:*.lzh=01;31:*.lzma=01;31:*.tlz=01;31:*.txz=01;31:*.zip=01;31:*.z=01;31:*.Z=01;31:*.dz=01;31:*.gz=01;31:*.lz=01;31:*.xz=01;31:*.bz2=01;31:*.bz=01;31:*.tbz=01;31:*.tbz2=01;31:*.tz=01;31:*.deb=01;31:*.rpm=01;31:*.jar=01;31:*.war=01;31:*.ear=01;31:*.sar=01;31:*.rar=01;31:*.ace=01;31:*.zoo=01;31:*.cpio=01;31:*.7z=01;31:*.rz=01;31:*.jpg=01;35:*.jpeg=01;35:*.gif=01;35:*.bmp=01;35:*.pbm=01;35:*.pgm=01;35:*.ppm=01;35:*.tga=01;35:*.xbm=01;35:*.xpm=01;35:*.tif=01;35:*.tiff=01;35:*.png=01;35:*.svg=01;35:*.svgz=01;35:*.mng=01;35:*.pcx=01;35:*.mov=01;35:*.mpg=01;35:*.mpeg=01;35:*.m2v=01;35:*.mkv=01;35:*.webm=01;35:*.ogm=01;35:*.mp4=01;35:*.m4v=01;35:*.mp4v=01;35:*.vob=01;35:*.qt=01;35:*.nuv=01;35:*.wmv=01;35:*.asf=01;35:*.rm=01;35:*.rmvb=01;35:*.flc=01;35:*.avi=01;35:*.fli=01;35:*.flv=01;35:*.gl=01;35:*.dl=01;35:*.xcf=01;35:*.xwd=01;35:*.yuv=01;35:*.cgm=01;35:*.emf=01;35:*.axv=01;35:*.anx=01;35:*.ogv=01;35:*.ogx=01;35:*.aac=00;36:*.au=00;36:*.flac=00;36:*.mid=00;36:*.midi=00;36:*.mka=00;36:*.mp3=00;36:*.mpc=00;36:*.ogg=00;36:*.ra=00;36:*.wav=00;36:*.axa=00;36:*.oga=00;36:*.spx=00;36:*.xspf=00;36:XDG_SESSION_PATH=/org/freedesktop/DisplayManager/Session0XDG_SEAT_PATH=/org/freedesktop/DisplayManager/Seat0SSH_AUTH_SOCK=/tmp/keyring-HrR3dS/sshSESSION_MANAGER=local/ubuntu:@/tmp/.ICE-unix/1370,unix/ubuntu:/tmp/.ICE-unix/1370DEFAULTS_PATH=/usr/share/gconf/ubuntu.default.pathXDG_CONFIG_DIRS=/etc/xdg/xdg-ubuntu:/etc/xdgPATH=/home/aits/bin:/usr/lib/lightdm/lightdm:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/gamesDESKTOP_SESSION=ubuntuPWD=/home/aits/534GNOME_KEYRING_PID=1359LANG=en_US.UTF-8MANDATORY_PATH=/usr/share/gconf/ubuntu.mandatory.pathUBUNTU_MENUPROXY=libappmenu.soCOMPIZ_CONFIG_PROFILE=ubuntuGDMSESSION=ubuntuSHLVL=1HOME=/home/aitsGNOME_DESKTOP_SESSION_ID=this-is-deprecatedLOGNAME=aitsXDG_DATA_DIRS=/usr/share/ubuntu:/usr/share/gnome:/usr/local/share/:/usr/share/DBUS_SESSION_BUS_ADDRESS=unix:abstract=/tmp/dbus-MKUBWsJj9t,guid=506ca60e0758d238806a3de600000015LESSOPEN=| /usr/bin/lesspipe %sDISPLAY=:0XDG_CURRENT_DESKTOP=UnityLESSCLOSE=/usr/bin/lesspipe %s %sCOLORTERM=gnome-terminalXAUTHORITY=/home/aits/.XauthorityOLDPWD=/home/aits_=./a.out

****************************************************************************/

/************************************************************************ 1(b)Aim:A Program to implement different types of exec functions Branch:III year CSE*************************************************************************/#includemain(){int r;char *cmd[]={"ls","-t",(char *)0};char *env[]={"home=/user/home","logname=home",(char *)0};char *argv[]={"/bin/ls","-t","-l",(char *)0};execl("/bin/ls","-r","-t","-l",(char *)0);execv("/bin/ls","-r","-t","-l",(char *)0);execle("/bin/ls","ls","-l",(char *)0);r=execlp("ls","ls","-l",(char *)0);r=execve("/bin/ls",cmd,env);r=execvp("ls",cmd);}

/*********************************************************************** outputaits@ubuntu:~$ vi different.caits@ubuntu:~$ cc different.caits@ubuntu:~$ ./a.outtotal 20-rw-rw-r-- 1 aits aits 700 Mar 4 14:48 different.c-rwxrwxr-x 1 aits aits 7353 Mar 4 14:35 a.out-rw-rw-r-- 1 aits aits 3103 Feb 25 16:36 display.c-rw-rw-r-- 1 aits aits 422 Feb 25 16:35 display.c~

***********************************************************************/

/************************************************************************2(a)Aim:A Program to create chain processes Branch:III year CSE*************************************************************************/#include#includeint main(){fork();fork();fork();printf("\nHELLO");}/************************************************************************* outputaits@ubuntu:~$ vi chain.caits@ubuntu:~$ cc chain.caits@ubuntu:~$ ./a.out

HELLOHELLOaits@ubuntu:~$ HELLOHELLOHELLOHELLOHELLOHELLO**************************************************************************/

/************************************************************************2(b)Aim:A Program to create chain processes and print the process id's Branch:III year, CSE*************************************************************************/#include#includeint main(){if(fork()==0){printf("%d%d\n",getpid(),getppid());if(fork()==0){printf("%d%d\n",getpid(),getppid());if(fork()==0)printf("%d%dhello()\n",getpid(),getppid());}}return 0;}/*************************************************************************outputaits@ubuntu:~$ vi process.caits@ubuntu:~$ cc process.caits@ubuntu:~$ ./a.outaits@ubuntu:~$ 283928382840283928412840hello()***************************************************************************/

/**************************************************************************** 2(c)Aim: A Program to create chain processes and print the process id's along with parent id's Branch:III year CSE****************************************************************************/#include#includeint main(){fork();printf("%d%d",getpid(),getppid());fork();printf("\nHELLO");fork();printf("\nHAI");}/**************************************************************************** outputaits@ubuntu:~$ vi pid.caits@ubuntu:~$ cc pid.caits@ubuntu:~$ ./a.out29202356HELLOHAI29202356HELLOHAIHELLOHAIHELLOHAIaits@ubuntu:~$ 29211HELLOHAI29211HELLOHAIHELLOHAIHELLOHAI****************************************************************************/

/**************************************************************************** 2(d)Aim: A Program to create chain processesto calculate the sum of odd numbers and even numbers Branch:III year CSE****************************************************************************/#include#include#include#includeint main(){int i,n,pid,tpid,sum=0;pid-tpid;system("clear");printf("\nenter n value");scanf("%d",&n);pid=fork();if(pid==0){printf("from chid process\n");for(i=1;i0&&(countmtype=1;strcpy(snd_msg->mtext,"hello world");snd=msgsnd(queue_id_rollno,snd_msg,strlen(snd_msg->mtext)+1,0);if(snd==-1){perror("main():message send error");exit(1);}free(snd_msg);printf("message placed on queue successfully\n");recv_msg=(struct msgbuf*)malloc(sizeof(struct msgbuf)+strlen("enter your msg receive"));rc=msgrcv(queue_id_rollno,recv_msg,strlen("enter your message to send")+1,0,0);if(rc==-1){perror("main():message receive error");exit(1);}printf("msgrcv:msg received in mtype=%d,mtext='%s'\n",recv_msg->mtype,recv_msg->mtext);return 0;}/**********************************************************Outputaits@ubuntu:~$ vi message.caits@ubuntu:~$ cc message.caits@ubuntu:~$ ./a.outmessage queue created,queued '131076'message placed on queue successfullymsgrcv:msg received in mtype=1,mtext='hello world'************************************************************/