Under linux, how to use C language to write programs to automatically modify network parameters Than

Modify network parameters? Can you elaborate on what you want to change?

The system() function can be called. Spell the Linux system command into a string, and then call system to execute the string. To modify the system configuration, the root identity is required.

1. system function:

prototype: int system(const char * command);

Function: Execute DOS (Windows) or Shell (Linux Unix) commands, and the parameter string command is the command name;

Note: In Windows, the system function invokes a command in the console. In Linux Unix, the system function will call the fork function to generate a child process, and the child process will execute the command command, and then return the original process after the command is executed.

Header Files:; Return value: 0 is returned if the command is successfully executed, and -1 is returned if the command is executed.

2. Example: include

#include

int main()

If you use it under Linux, writing an interactive and friendly shell script is the least expensive, and the cost of implementing it in C language is too high, and there are a lot of source code analysis of ifconfig route, not to mention DHCP, DNS and user management.

In fact, the above requirements directly have ready-made instructions or system calls, and it is OK to process them with shell.

Runtime with the command: nice

Syntax: nice [-increment |n increment ] command [parameter ..

For example, your program is called , no arguments, and has a priority of -19:

nice -19

The increment values range from 1-19, the default value is 10, you make it 20, and it runs at 19.

If you have a nice function in your C, you can set the run priority, otherwise it will be given at runtime. If you have admin privileges, you can also use Renice to change priority

In the Linux terminal, the steps to compile a C program are as follows:

Use vi to write the source **, and after the writing is completed, :wq is saved and exited, such as:

vi On the command line, run the gcc compiler to generate the execution code, such as:

gcc -o test

o indicates the name of the executor code generated.

Run the compiled execution code.

test

Just write your own login.

However, many graphical login managers support automatic login.

I remember the character interface was to modify the initrd, and replace the command that ran the login program with a direct launch of the command interpreter.

Is it possible to log in to a remote Linux server via SSH?