First Landing on Ubuntu with Linux gcc and native command

dual boot with Windows 10 off an DVD 
sudo apt-get install gcc
gcc hw.c, ./a.out, sudo cat foo
sudo pm-hibernate

python3 hw.py
#!/usr/bin/python3
import os

fout=os.open("foo2",os.O_WRONLY|os.O_CREAT,0o644)

os.write(fout,bytes("hello Python on Lunux","utf-8"))
os.close(fout)

qt creator IDE c or C++ project but buggy for include and intellisense
gcc -H hw.c show all header files
eclipse C/C++ IDE (Mars) preference Editor/Adance check proposal will
assit intellisence, use ctrl-space to get O_WRONLY

eclipse install new software menu-> http://pydev.org/updates will install Python IDE.
note that Ubuntu has Phython 3 installed

Linux Concurrency intervening

int main()
{
 int i,j=0;
 if(fork())
  while(i++<100)   printf("parent %d\n ",getpid());
 else
  while(j++<100) printf("child %d\n",getpid());
}

Linux Concurrency synchronize by signal
header files stdio.h, stdlib.h 
must include string.h for strsignal or segmentation fault for strsignal(WTERMSIG(status))
int main()
{
 int status;
 if(fork())
 {
      wait(&status);
      if(WIFEXITED(status))
        printf("exit status %d\n ",WEXITSTATUS(status));
      if(WIFSIGNALED(status))
       printf("signal status %d: %s\n",WTERMSIG(status),strsignal(WTERMSIG(status)));  
 }
 else
 {
   *(int*)0=99;  // segmentation fault
   exit(3);
 }
}


Pipe:

mkfifo /tmp/jqd
ls -l /tmp
cat /tmp/jqd (blocking) until another terminal date> /tmp/jqd