Question: How can change the program with the C mail command?
  like mail(addr,subj,mesg)

/*       Mail program for Aix
     by
           Harry Tempelman

  Compiler   : Aix RS/6k cc
  Machine       : AIX 340
  Date          : 16-SEP-93  */

#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <string.h>
#include <time.h>
#include <sys/param.h>
#include <unistd.h>

void main(void);

void main(void)
{
 FILE *fp;
 char hostname[]= "APEX", user1[]= "operator", user2[]= "root";
 char subj[]= "TimeOut_program";
 char TmpFile[]= "/tmp/TmpMail";
 char invoker[80];
 char   addr[125];
 char   mesg[125];
 char    Cmd[255];

 char *s;
 struct tm *p_tm;
 time_t t;
 time ( &t );

 strcpy(invoker, getlogin( ) );

 sprintf( mesg,"\n\tLogged out user %s on %s\n\n",invoker, asctime( localtime(&t)) );
 sprintf( addr,"%s@%s %s@%s",user1, hostname, user2, hostname );

 fp = fopen( TmpFile,"w" );

 fprintf( fp, "%s\n",mesg );
 fclose( fp );
 sprintf( Cmd,"Mail -s %s %s </tmp/TmpMail", subj, addr );
 system( Cmd );
 remove(TmpFile);
}

 APEX METALS INC.   .   .   .   .    __|__    .   . harry.tempelman@canrem.com
   .   .   .   .   .   .   . --o--o--(_)--o--o-- .   .   .   .   .   .   .   .
---
     DeLuxe    1.25 #11534     REALITY.SYS Corrupted: Reboot universe? [Y/N]