first commit

01_Write.c

@@ -1,12 +1,12 @@
-// Q. To write some data on the standard output device (by default � monitor)
+// Q. To write some data on the standard output device (by default monitor)
 
 #include <stdio.h>
 #include <unistd.h>
 
 int main()
 {
 	// This contains number of bytes read
-	int count; 	
+	int count;
 
 	// 1			--> The file descriptor (stdout)
 	// "Hello Linux!\n"	--> The data
@@ -18,10 +18,10 @@ int main()
 
 /*
 	Output:
-	
+
 	s4shibam@SHIBAM:~/OS$ gcc 01_Write.c
 	s4shibam@SHIBAM:~/OS$ ./a.out
-	Hello Linux!                                                                                                         
+	Hello Linux!
 	Total bytes written: 13.
 	s4shibam@SHIBAM:~/OS$
 */

02_Read.c

@@ -3,29 +3,29 @@
 #include <stdio.h>
 #include <unistd.h>
 
-int main ()
+int main()
 {
 	// This contains number of bytes read
-	int len;	
-	
+	int len;
+
 	// Read maximum 50 bytes from standard input device (0 --> stdin)
 	// & store in buffer (ch)
 	char ch[50];
-	len = read (0, ch, 50);	
-	
+	len = read(0, ch, 50);
+
 	// Write "len" bytes from the buffer on screen
-	write (1, ch, len);
-	printf ("\nTotal bytes written: %d.\n", len);
+	write(1, ch, len);
+	printf("\nTotal bytes written: %d.\n", len);
 }
 
 /*
- 	Output:
- 	
- 	s4shibam@SHIBAM:~/OS$ gcc 2_read.c
+	Output:
+
+	s4shibam@SHIBAM:~/OS$ gcc 2_read.c
 	s4shibam@SHIBAM:~/OS$ ./a.out
 	Hello Dear Linux!
 	Hello Dear Linux!
-	
+
 	Total bytes written: 18.
 	s4shibam@SHIBAM:~/OS$
 */

03_Open_And_Read_Existing_File.c

@@ -1,36 +1,37 @@
 // Q. Write a program using open() system call to read data from (max 50 char)
-// an existing file “Text1.txt” and print them on screen.
+// an existing file �Text1.txt� and print them on screen.
 
 #include <stdio.h>
 #include <unistd.h>
 #include <sys/types.h>
 #include <sys/types.h>
 #include <fcntl.h>
 
-int main (){
-
+int main()
+{
+
 	int len, fd;
 	char ch[50];
-	
+
 	// Opens test.txt in read mode and
 	// the file descriptor is saved in integer fd
-	fd = open("Text1.txt", O_RDONLY);	
-	
+	fd = open("Text1.txt", O_RDONLY);
+
 	// The value of the file descriptor is printed.
-	printf("The file descriptor of the file is: %d\n", fd); 
-	
+	printf("The file descriptor of the file is: %d\n", fd);
+
 	// Read maximum 50 characters from the file pointed by file descriptor fd
 	// and save them in buffer (ch)
 	len = read(fd, ch, 50);
 
 	// Write on the screen from the buffer
-	write(1, ch, len); 
+	write(1, ch, len);
 	printf("\nTotal bytes written: %d.\n", len);
 }
 
 /*
 	Output:
-	
+
 	s4shibam@SHIBAM:~/OS$ gcc 3_Open_And_Read_Existing_File.c
 	s4shibam@SHIBAM:~/OS$ ./a.out
 	The file descriptor of the file is: 3

04_Open_Read_And_Write_In_New_File.c

@@ -1,44 +1,45 @@
 // Q. Write a program using open() system call to read data from (max 50 char)
-// an existing file “Text1.txt” and write them into non-existing file “Text2.txt”
+// an existing file �Text1.txt� and write them into non-existing file �Text2.txt�
 
 #include <stdio.h>
 #include <unistd.h>
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <fcntl.h>
 
-int main (){
-
+int main()
+{
+
 	int len, fd, fd1;
 	char ch[50];
-	
+
 	// Opens test.txt in read mode and
 	// the file descriptor is saved in integer fd
-	fd = open("Text1.txt", O_RDONLY);	
-	
+	fd = open("Text1.txt", O_RDONLY);
+
 	// The value of the file descriptor is printed.
-	printf("The file descriptor of the file is: %d\n", fd); 
-	
+	printf("The file descriptor of the file is: %d\n", fd);
+
 	// Read maximum 50 characters from the file pointed by file descriptor fd
 	// and save them in buffer (ch)
 	len = read(fd, ch, 50);
-	
+
 	// New file is created in write only mode and
 	// the file descriptor is saved in integer fd1
 	// Pipe symbol (|) is used to separate O_WRONLY and O_CREAT
 	fd1 = open("Text2.txt", O_WRONLY | O_CREAT, 0642);
 
 	// Write in the Text2.txt file from the buffer
-	write(fd1, ch, len); 
+	write(fd1, ch, len);
 	printf("\nTotal bytes written: %d.\n", len);
 }
 
 /*
 	Output:
-	
+
 	s4shibam@SHIBAM:~/OS$ gcc 4_Open_Read_And_Write_In_New_File.c
 	s4shibam@SHIBAM:~/OS$ ./a.out
 	The file descriptor of the file is: 3
 	Total bytes written: 23.
-	s4shibam@SHIBAM:~/OS$ 
+	s4shibam@SHIBAM:~/OS$
 */

05_Open_Read_And_Append_In_Existing_File.c

@@ -1,43 +1,43 @@
 // Q. Write a program using open() system call to read data from (max 50 char)
-// the standard input device and append them into existing file “Text3.txt”
-
+// the standard input device and append them into existing file �Text3.txt�
 
 #include <stdio.h>
 #include <unistd.h>
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <fcntl.h>
 
-int main (){
-
+int main()
+{
+
 	int len, fd, fd1;
 	char ch[50];
 	char append[50];
- 	
+
 	// Read maximum 50 bytes from standard input device (0 --> stdin)
 	// & store in buffer (ch)
 	len = read(0, append, 50);
-	
-	printf("Total bytes read: %d.\n", len); 
-	
+
+	printf("Total bytes read: %d.\n", len);
+
 	// Existing file is opened in append mode and
 	// the file descriptor is saved in integer fd
 	// Pipe symbol (|) is used to separate O_WRONLY and O_APPEND
 	fd = open("Text3.txt", O_WRONLY | O_APPEND);
-	
+
 	// Append in the Text3.txt file from the buffer
-	write(fd, append, len); 
+	write(fd, append, len);
 	printf("\nTotal bytes appended: %d.\n", len);
 }
 
 /*
 	Output:
-	
- 	s4shibam@SHIBAM:~/OS$ gcc 5_Open_Read_And_Append_In_Existing_File.c
+
+	s4shibam@SHIBAM:~/OS$ gcc 5_Open_Read_And_Append_In_Existing_File.c
 	s4shibam@SHIBAM:~/OS$ ./a.out
 	This is the appended line!
 	Total bytes read: 27.
-	 
+
 	Total bytes appended: 27.
-	s4shibam@SHIBAM:~/OS$ 
+	s4shibam@SHIBAM:~/OS$
 */

06_Create_Child_Process.c

@@ -8,39 +8,42 @@
 int main()
 {
 	int f;
-	
-	printf ("Before fork!\n");
-	f = fork();	
-	
+
+	printf("Before fork!\n");
+	f = fork();
+
 	// The creation of the process was unsuccessful
-	if (f < 0){
-
-		printf ("Error occurred!\n");
+	if (f < 0)
+	{
+
+		printf("Error occurred!\n");
 	}
-	
+
 	// Child process
-	else if (f == 0){
-
-		printf ("This is Child Process!\n");
-		printf ("Child: Child Process pid: %d\n", getpid());
-		printf ("Child: Parent Process pid: %d\n", getppid());
+	else if (f == 0)
+	{
+
+		printf("This is Child Process!\n");
+		printf("Child: Child Process pid: %d\n", getpid());
+		printf("Child: Parent Process pid: %d\n", getppid());
 	}
-	
+
 	// Parent process
-	else {
-
-		printf ("This is Parent Process!\n");
-		printf ("Parent: Parent Process pid: %d\n", getpid());
-		printf ("Parent: Child Process pid: %d\n", f);
+	else
+	{
+
+		printf("This is Parent Process!\n");
+		printf("Parent: Parent Process pid: %d\n", getpid());
+		printf("Parent: Child Process pid: %d\n", f);
 	}
-	
-	// This part will be executed by both child & parent 
-	printf ("This is common!\n");
+
+	// This part will be executed by both child & parent
+	printf("This is common!\n");
 }
 
 /*
 	Output:
-	
+
 	s4shibam@SHIBAM:~/OS$ gcc 6_Create_Child_Process.c
 	s4shibam@SHIBAM:~/OS$ ./a.out
 	Before fork!
@@ -51,6 +54,6 @@ int main()
 	Parent: Child Process pid: 1869
 	Child: Parent Process pid: 1868
 	This is common!
-	This is common! 
-	s4shibam@SHIBAM:~/OS$ 
+	This is common!
+	s4shibam@SHIBAM:~/OS$
 */

07_Wait_In_Process.c

@@ -8,41 +8,44 @@
 int main()
 {
 	int f;
-	
-	printf ("Before fork!\n");
-	f = fork();	
-	
+
+	printf("Before fork!\n");
+	f = fork();
+
 	// The creation of the process was unsuccessful
-	if (f < 0){
-
-		printf ("Error occurred!\n");
+	if (f < 0)
+	{
+
+		printf("Error occurred!\n");
 	}
-	
+
 	// Child process
-	else if (f == 0){
-
-		printf ("This is Child Process!\n");
-		printf ("Child: Child Process pid: %d\n", getpid());
-		printf ("Child: Parent Process pid: %d\n", getppid());
+	else if (f == 0)
+	{
+
+		printf("This is Child Process!\n");
+		printf("Child: Child Process pid: %d\n", getpid());
+		printf("Child: Parent Process pid: %d\n", getppid());
 	}
-	
+
 	// Parent process
-	else {
-
+	else
+	{
+
 		// Parent process will wait until execution of the child process
 		wait(NULL);
-		printf ("This is Parent Process!\n");
-		printf ("Parent: Parent Process pid: %d\n", getpid());
-		printf ("Parent: Child Process pid: %d\n", f);
+		printf("This is Parent Process!\n");
+		printf("Parent: Parent Process pid: %d\n", getpid());
+		printf("Parent: Child Process pid: %d\n", f);
 	}
-	
-	// This part will be executed by both child & parent 
-	printf ("This is common!\n");
+
+	// This part will be executed by both child & parent
+	printf("This is common!\n");
 }
 
 /*
 	Output:
-	
+
 	s4shibam@SHIBAM:~/OS$ gcc 7_Wait_In_Process.c
 	s4shibam@SHIBAM:~/OS$ ./a.out
 	Before fork!
@@ -54,6 +57,6 @@ int main()
 	Parent: Parent Process pid: 1979
 	Parent: Child Process pid: 1980
 	This is common!
-	s4shibam@SHIBAM:~/OS$ 
-	
+	s4shibam@SHIBAM:~/OS$
+
 */