diff --git a/6.process_and_signal/file_communication.c b/6.process_and_signal/file_communication.c
new file mode 100644
index 0000000..3ab6823
--- /dev/null
+++ b/6.process_and_signal/file_communication.c
@@ -0,0 +1,72 @@
+#include <unistd.h>
+#include <stdio.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <dirent.h>
+#include <fcntl.h>
+#include <ctype.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <signal.h>
+
+void sigusr1action (int signal){
+     
+     fprintf(stdout,"Parent:Ricevuto SIGUSR1\n");
+     
+}
+
+void sigchldaction (int signal){
+
+    fprintf(stdout,"Parent:Ricevuto SIGCHLD\n");
+
+     
+}
+
+
+int main (int index, char** in_data){
+     
+    int duplicate;
+    duplicate = fork();
+    if (duplicate < 0)
+          exit(-1);
+    if (duplicate == 0){
+     //child
+     
+          int numero;
+          fscanf(stdin,"%d",&numero);
+          kill (getppid(),SIGUSR1);
+          fprintf(stdout,"Child:Process %d terminated\n",getpid());
+     
+    }else{
+     // parent
+     
+          struct sigaction sigusr1structure;
+               sigusr1structure.sa_handler = sigusr1action;
+               sigusr1structure.sa_flags = 0;
+          
+         
+          struct sigaction sigchldstructure;
+               sigchldstructure.sa_handler = sigchldaction;
+               sigchldstructure.sa_flags = 0;
+          
+         
+         sigaction (SIGUSR1, &sigusr1structure, NULL);
+         sigaction (SIGCHLD, &sigchldstructure, NULL);
+         
+          int status;
+          int pid;
+          
+          for (pid = waitpid(-1,&status,0);pid > 0;pid = waitpid(-1,&status,0)){
+               fprintf(stdout,"Parent:Child %d terminated\n",pid);
+          }
+         
+         fprintf(stdout,"Parent:Process %d terminated\n",getpid());
+    }
+    
+    
+    
+     
+     return 0;
+}
+
diff --git a/6.process_and_signal/waitc b/6.process_and_signal/waitc
new file mode 100755
index 0000000..231ba34
Binary files /dev/null and b/6.process_and_signal/waitc differ
diff --git a/6.process_and_signal/waitc.c b/6.process_and_signal/waitc.c
new file mode 100644
index 0000000..3ab6823
--- /dev/null
+++ b/6.process_and_signal/waitc.c
@@ -0,0 +1,72 @@
+#include <unistd.h>
+#include <stdio.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <dirent.h>
+#include <fcntl.h>
+#include <ctype.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <signal.h>
+
+void sigusr1action (int signal){
+     
+     fprintf(stdout,"Parent:Ricevuto SIGUSR1\n");
+     
+}
+
+void sigchldaction (int signal){
+
+    fprintf(stdout,"Parent:Ricevuto SIGCHLD\n");
+
+     
+}
+
+
+int main (int index, char** in_data){
+     
+    int duplicate;
+    duplicate = fork();
+    if (duplicate < 0)
+          exit(-1);
+    if (duplicate == 0){
+     //child
+     
+          int numero;
+          fscanf(stdin,"%d",&numero);
+          kill (getppid(),SIGUSR1);
+          fprintf(stdout,"Child:Process %d terminated\n",getpid());
+     
+    }else{
+     // parent
+     
+          struct sigaction sigusr1structure;
+               sigusr1structure.sa_handler = sigusr1action;
+               sigusr1structure.sa_flags = 0;
+          
+         
+          struct sigaction sigchldstructure;
+               sigchldstructure.sa_handler = sigchldaction;
+               sigchldstructure.sa_flags = 0;
+          
+         
+         sigaction (SIGUSR1, &sigusr1structure, NULL);
+         sigaction (SIGCHLD, &sigchldstructure, NULL);
+         
+          int status;
+          int pid;
+          
+          for (pid = waitpid(-1,&status,0);pid > 0;pid = waitpid(-1,&status,0)){
+               fprintf(stdout,"Parent:Child %d terminated\n",pid);
+          }
+         
+         fprintf(stdout,"Parent:Process %d terminated\n",getpid());
+    }
+    
+    
+    
+     
+     return 0;
+}
+