余森彬 justdoit0823

## netcat_examples.md

      
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                justdoit0823
                / netcat_examples.md
            
            
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              April 15, 2023 20:23
            
              
                A collection of examples about using netcat.
              
          
    Netcat Examples

Establish TCP Connection


Connect to network host over TCP connection


## http_message_versus_entity.md

      
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                justdoit0823
                / http_message_versus_entity.md
            
            
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              January 6, 2018 12:16
            
              
                A comparision between http message and entity.
              
          
    Message


HTTP messages consist of requests from client to server and responses
from server to client.

HTTP-message   = Request | Response     ; HTTP/1.1 messages
generic-message = start-line


## show_libraries_referenced_by_executables.md

      
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                justdoit0823
                / show_libraries_referenced_by_executables.md
            
            
              Created
              November 23, 2017 13:02
            
              
                List all libraries used by executables on linux.
              
          
    Command


ldd

lddb executable_file

In some circumstances, some versions of ldd may attempt to obtain the dependency information by directly executing the program.

  
## inspect_multithread.sh

# get processes with related threads
ps -eLf |grep "process name"

# list all opened file descriptors in a process PID and under which thread
lsof -aKp PID

# trace syscalls in a process's main thread or other thread PID
strace -p PID

## inspect-descriptor.c

#include "Python.h"


PyTypeObject * create_type(const char * name){
  PyObject * args, * dict, * value;
  PyTypeObject * type;

  args = PyTuple_New(3);
  PyTuple_SetItem(args, 0, PyUnicode_FromString(name));

## beijing_public_telephone.js
var tables = document.getElementsByTagName('table');

for(var i=0; i < tables.length; i ++) {
	for(var j=0; j < tables[i].childNodes[0].childNodes.length; j++){
		if(j == 0) {
		  console.log('====' + tables[i].childNodes[0].childNodes[j].innerText + '=====');
		}
		else {
		  console.log(tables[i].childNodes[0].childNodes[j].childNodes[0].innerText, tables[i].childNodes[0].childNodes[j].childNodes[1].innerText);
		}

## load_csv_into_mysql.sql

load data infile 'src.csv' into table dest_table FIELDS TERMINATED BY ',' ENCLOSED BY '"';

## file-lock-in-child-process.md

      
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                / file-lock-in-child-process.md
            
            
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                how file lock is handled in child process.
              
          
File Record lock

As well as being removed by an explicit F_UNLCK, record locks are automatically released when the process terminates or if it closes any file descriptor referring to a file on which locks are held.  This is bad: it means that a process can lose the locks on a file like /etc/passwd or /etc/mtab when for some reason a library function decides to open, read and close it.
Record locks are not inherited by a child created via fork(2), but are preserved across an execve(2).
Because of the buffering performed by the stdio(3) library, the use of record locking with routines in that package should be avoided; use read(2) and write(2) instead.

  
## emacs-startup.el
(defun load-protobuf ()
  "Load protobuf."
  (add-to-list 'load-path "~/.emacs.d/el-get/protobuf-mode")
  (require 'protobuf-mode)
  (add-to-list 'auto-mode-alist '("\\.proto\\'" . protobuf-mode))
  (add-hook 'protobuf-mode-hook (lambda () (auto-complete-mode)))
  )

## hll-in-postgresql.sql

drop table if exists s_user_table;
create table s_user_table (
       id int,
       user_id int
);


drop table if exists s_user_cnt_table;
create table s_user_cnt_table (

	# get processes with related threads
	ps -eLf \|grep "process name"

	# list all opened file descriptors in a process PID and under which thread
	lsof -aKp PID

	# trace syscalls in a process's main thread or other thread PID
	strace -p PID

	#include "Python.h"


	PyTypeObject * create_type(const char * name){
	PyObject * args, * dict, * value;
	PyTypeObject * type;

	args = PyTuple_New(3);
	PyTuple_SetItem(args, 0, PyUnicode_FromString(name));
	var tables = document.getElementsByTagName('table');

	for(var i=0; i < tables.length; i ++) {
	for(var j=0; j < tables[i].childNodes[0].childNodes.length; j++){
	if(j == 0) {
	console.log('====' + tables[i].childNodes[0].childNodes[j].innerText + '=====');
	}
	else {
	console.log(tables[i].childNodes[0].childNodes[j].childNodes[0].innerText, tables[i].childNodes[0].childNodes[j].childNodes[1].innerText);
	}

	load data infile 'src.csv' into table dest_table FIELDS TERMINATED BY ',' ENCLOSED BY '"';
	(defun load-protobuf ()
	"Load protobuf."
	(add-to-list 'load-path "~/.emacs.d/el-get/protobuf-mode")
	(require 'protobuf-mode)
	(add-to-list 'auto-mode-alist '("\\.proto\\'" . protobuf-mode))
	(add-hook 'protobuf-mode-hook (lambda () (auto-complete-mode)))
	)

	drop table if exists s_user_table;
	create table s_user_table (
	id int,
	user_id int
	);


	drop table if exists s_user_cnt_table;
	create table s_user_cnt_table (