Shell Programming and Scripting

awk '/<?xml\ version/{i++}{print > "outfile."i}' test123.xml

awk '
    function ts(    c )     # timestamp with nano sec
    {
        c = "date --rfc-3339=ns | sed -E \"s/(..)-(..)-/\1\2/;s/ //; s/-.*//;s/://g\"";
        c | getline timestamp;
        close( c );
    }

    /<?xml\ version/{ ts(); }{ print >"outfile." timestamp; } ' in-file

#include <unistd.h>
#include <stdio.h>
#include <time.h>
#include <sys/time.h>

int main( )
{
    struct tm ltime;
    struct timeval tv;
    time_t  now;

    now = time( NULL );
    localtime_r( &now, &ltime );
    gettimeofday( &tv, NULL );
    printf( "%4d%02d%02d%02d%02d%02d.%d\n", ltime.tm_year + 1900, ltime.tm_mon + 1, ltime.tm_mday, ltime.tm_hour, ltime.tm_min, ltime.tm_sec, tv.tv_usec );

    return 0;
}

cc -o datens datens.c