How to do “mysqladmin flush-hosts” on server?

I got mysql error:

ERROR 1129 (HY000): Host 'xxx.xxx.xxx.xxx' is blocked because of many connection errors; unblock with 'mysqladmin flush-hosts'

Resolve:

mysql -u root -p -e 'flush hosts'

While loop with promises

var Q = require("q");

// `condition` is a function that returns a boolean
// `body` is a function that returns a promise
// returns a promise for the completion of the loop
function promiseWhile(condition, body) {
    var done = Q.defer();

    function loop() {
        // When the result of calling `condition` is no longer true, we are
        // done.
        if (!condition()) return done.resolve();
        // Use `when`, in case `body` does not return a promise.
        // When it completes loop again otherwise, if it fails, reject the
        // done promise
        Q.when(body(), loop, done.reject);
    }

    // Start running the loop in the next tick so that this function is
    // completely async. It would be unexpected if `body` was called
    // synchronously the first time.
    Q.nextTick(loop);

    // The promise
    return done.promise;
}


// Usage
var index = 1;
promiseWhile(function () { return index <= 11; }, function () {
    console.log(index);
    index++;
    return Q.delay(500); // arbitrary async
}).then(function () {
    console.log("done");
}).done();

http://stackoverflow.com/questions/17217736/while-loop-with-promises

clear log file

1. #cat /dev/null >/var/log/error.log (command is "cat")
2. #>/var/log/error.log (command is ">")

Deep first search - unrecursion

def deep_first_search(vpath):
root = Node(vpath)
node = root
while True:
objs = list_directory(node.name)
for obj in objs:
child = Node(node.name + obj['objname'] + '/', node)
node.set_child(child)
first_child = node.first_child
if first_child:
node = first_child
else:
while not node.has_next_sibling:
if node is root:
break
if node is root:
first_child = node.first_child
if first_child:
node = first_child
continue
else:
break
tmp = node
node = node.next_sibling(node)
node.remove_sibling(tmp)

class Node(object):
"""docstring for Node"""
def __init__(self, name, parent=None):
super(Node, self).__init__()
self.__name = name
self.__parent = parent
self.__child_nodes = []

@property
def has_next_sibling(self):
try:
if self.__parent != None:
return len(self.__parent.__child_nodes) > 1
else:
return False
except (IndexError, AttributeError):
return False

@property
def name(self):
return self.__name

@property
def parent(self):
return self.__parent

@property
def first_child(self):
try:
return self.__child_nodes[0]
except (IndexError, AttributeError):
return None

def next_sibling(self, node):
try:
if self.__parent != None:
i = self.__parent.__child_nodes.index(node)
return self.__parent.__child_nodes[i+1]
else:
return None
except (IndexError, AttributeError):
return None

def set_child(self, node):
self.__child_nodes.append(node)

def remove_child(self, node):
try:
self.__child_nodes.remove(node)
except Exception, e:
raise e

def remove_sibling(self, node):
try:
self.__parent.__child_nodes.remove(node)
except Exception, e:
raise e

All file modes in Python

• r for reading
• w for writing
• r+ opens for reading and writing (cannot truncate a file)
• w+ for writing and reading (can truncate a file)
• rb+ reading or writing a binary file
• wb+ writing a binary file
• a+ opens for appending

run command with another user on debian

su -c "command here" -s /bin/sh another_user_here

example:

#su -c "cat /etc/groups" -s /bin/sh www-data

get all files or subdirectories in directory

cách 1:
>> liệt kê file và directory

#ls -l | awk '{print $9}'

>> liệt kê cả file ẩn

#ls -la | awk '{print $9}'

>> nếu chỉ muốn liệt kê directory

#ls -l | grep ^d | awk '{print $9}' 

>> nếu chỉ muốn liệt kê file

#ls -l | grep -v ^d | awk '{print $9}' 

cách 2:

#find . -maxdepth 1 -type f

>> xem kết quả

./.DS_Store

./03.mp3

./13ductinh.txt

./EsuDotNet_2.1.4.31.zip

./get_test.txt

./test

#str_to_rep=""
#for item in `find . -maxdepth 1 -type f`; do
#filename="${filename//.\//str_to_rep}"
#echo $filename
#done

>> kết quả

.DS_Store

03.mp3

13ductinh.txt

EsuDotNet_2.1.4.31.zip

get_test.txt

test

>> nếu không muốn hiển thị file ẩn

#find . -not -path '*/\.*' -maxdepth 1 -type f