Tip: Disable echo output from Linux terminal

Article Title: tip: "Disable" Echo output from Linux terminal. Linux is a technology channel of the IT lab in China. Includes basic categories such as desktop applications, Linux system management, kernel research, embedded systems, and open source.

The Termios structure is a standard interface defined in the POSIX specification. You can control the terminal interface by setting the data structure value of the termios type and calling related functions.

The output ECHO of the control terminal mainly uses the macro ECHO of c_lflag available in "Local Mode". The ECHO macro is defined as: enable the local ECHO function of input characters.

The most common application of this function is to control the echo of the input password. For example, the password entered during logon to MySQL through sudo/etc/** is not displayed.

The definition of the termios structure is included in the termios. h header file. You can view the Code directly:

　　

# Include # define PASSWORD_LEN 12int main () {struct termios initialrset.pdf, newrset.pdf; char password [PASSWORD_LEN + 1]; tcgetattr (fileno (stdin), & initirsalet.pdf ); # obtain the termios structure and save newrsettings = initialrsettings; newrsettings. c_lflag & = ~ ECHO; # Clear the bit printf ("Please Enter Password:") defined by ECHO in the variable c_lflag; if (tcsetattr (fileno (stdin), TCSAFLUSH, & newrsetush )! = 0) {fprintf (stderr, "cocould not set arrributes \ n");} else {fgets (password, PASSWORD_LEN, stdin); tcsetattr (fileno (stdin), TCSANOW, & initialrsettings); # restore the previous termios structure fprintf (stdout, "\ nYou entered % s as the password \ n", password);} exit (0 );}

 

Finally, compile and run the program for the expected purpose ~

The header files to be included in different Linux distributions may be slightly different. The following is my host information:

　　

Hardware:i686OS:Linux (ubuntu desktop 7.10)Release:2.6.22-14-genericVersion:#1 SMP Tue Feb 12 07:42:25 UTC 2008