Python errors and exceptions, re-modules, multi-threading, Paramiko modules

File operations
X=open ('/etc/hosts ') # # #默认读的方式打开
X.readline ()
X.read ()
X.seek (0)
Y=open ('/root/new.txt ', ' W ')
Y.writelines (' abcd\n ')
Y.flush () Save
Y.close ()

Function
def function name (x,y=11):
Command

Function name (' Tom ', ' Jerry ')

Nameerrot Error not declared
Indexerror No Index
SyntaxError syntax error
Keyboardinterrupt user presses CTRL + C (interrupt) error
Eoferror ctrl+d Error
Ioerrot Input/output operation failed
Zerodivisionerror integer divisible error (such as 3/0 error)
ValueError value error (such as String is not an integer)
###############################
Set error # #可以把多个excep语句连接在一起 to handle multiple exceptions that may occur in a try block
#!/usr/bin/python
#coding: Utf-8
Try
Raw_input (' Please enter user name: ')
Except Keyboardinterrupt: # #如果上面结果出现异常KeyboardInterrupt (CTRL + C) Error print CTRL + C
print ' \ n You pressed CTRL + C '
Except Eoferror: # #如果上面结果出现异常EOFError错误 Print Ctrl+d
print ' \ n you pressed Ctrl+d '.
Except: # #如果上面结果出现其他异常错误 Print you made a mistake.
print ' Went wrong '
#################################
Number error
#!/usr/bin/python
#coding: Utf-8
Try
X=int (raw_input (' Please enter Number: '))
Print 3/x
Except Zerodivisionerror:
print ' cannot enter 0 '
Except ValueError:
print ' You're not typing a number '
#################################
Assigning the wrong content to a variable
#!/usr/bin/python
#coding: Utf-8
Try
X=int (raw_input (' Please enter Number: '))
Print 3/x
Except Zerodivisionerror,e:
print ' You're wrong ', E
Except ValueError:
print ' You're not typing a number '

###################################
#!/usr/bin/python
#coding: Utf-8
Try
X=int (raw_input (' Enter Number: ') # #输入字符串, convert to an integer, and assign to X
Print 3/x
Except Zerodivisionerror,e:
print ' You're wrong ', E
Except ValueError:
print ' You're not typing a number '
Else
print ' No problem ' # #不出错执行
Finally
print ' Game over ' # #出不出错都执行
#######################################
Determine if the file is closed

>> x=open ('/etc/hosts ')
>> x.closed # #文件关闭了吗
False
>> x.close () # #关闭文件
>> x.closed
True
##################################
>> with open ('/etc/hosts ') as x: # #将打开的文件操作放在with语句中的x内, code ending without indentation, file automatically closed
... x.readline () # #读一行包含结束符号 \ n
... x.readline () # #读一行包含结束符号 \ n
... # #没有缩进代表结束
' 127.0.0.1 localhost localhost.localdomain localhost4 localhost4.localdomain4\n ' # #文件第一行
':: 1 localhost localhost.localdomain localhost6 localhost6.localdomain6\n ' # #文件第二行
>> x.closed # #文件关闭了吗
True # #关闭

#################################
The result of a conditional judgment command
#!/usr/bin/python
#coding: Utf-8
X=int (raw_input (' Please enter 1-100 number: '))
Try
If x>100:
Raise ValueError, ' value cannot be greater than ' # ' #把x的结果触发为异常ValueError
If x<1:
Raise ValueError, ' value cannot be less than 1 '
Except Valueerror,e: # #如果异常出现ValueError, give the content to E
Print E # #打印错误显示的内容

########################################
Re module
################################

>> Import re
Re.match regular matches, matches only the beginning ^
>> x=re.match (' Hello ', ' hello the World ')
>> X.group ()
' Hello '

>> Import re
Re.search matches, matches all positions, matches only the first
X=re.search (' The ', ' Hello the Wod,,he app ')
>> X.group ()
' The '

>> Import re
Re.findall regular match, match all positions, all content
>> X=re.findall (' The ', ' Hello the Wod,,the app ')
>> x
[' The ', ' the ']

>> Import re
>> m=re.finditer (' foo ', ' Seafood ' food ')
>> for item in M:
... print item.group ()
...
Foo
Foo

>> patt=re.compile (' foo ') # #把foo编译成二进制, passed to Patt
>> m=patt.match (' food ') # #在food内容中匹配到foo, passed to M
>> Print M.group () # #显示m的内容
Foo

>> mylist=re.split ('. | -', ' Hello-world.data ') # #使用. Or-as a delimiter, divide the string into a list and give the result to MyList
>> Print MyList
[' Hello ', ' world ', ' data ']

>> m=re.sub (' X ', ' mr.smith ', ' Attn:x\ndearx ') # #把X替换成Mr. Smith
>> Print M
Attn:Mr.smith
Dearmr.smith

###################################################
Use awk to count the number of IPs in the log content
awk ' {ip[$1]++} end{for (i in IP) {print i,ip[i]}} ' per IP access count

###################################################
Count the number of browsers accessed with Firefox and Curl
#!/usr/bin/python
#coding: Utf-8
Import re
Z=0
File1=open ('/var/log/httpd/access_log ')
For I in File1:
X=re.search (' Firefox ', i)
If x:
Z+=1
File1.close ()
print ' Number of Firefox is%d '%z
G=0
File2=open ('/var/log/httpd/access_log ')
For I in File2:
X=re.search (' curl ', i)
If x:
G+=1
File2.close ()
print ' number of curl is%d '%g
#################################
Relative to the previous script simply some dictionary {' subscript ': value, ' subscript ': Value,.....} dic.get (key,0) subscript key to take key (subscript) value, no take 0
#!/usr/bin/python
#coding: Utf-8
Import re
dic={} # # #为字典
Data=open ('/var/log/httpd/access_log ')
For I in data:
m = Re.search (' (firefox|curl) ', i) # #把匹配的内容给m
If M: # #如果m存在, go on down here.
Key=m.group () # # #取出m的内容, become key
Dic[key]=dic.get (key,0) +1 # # #累加dic字典下标firefox的值
Print dic
###########################################
Python Auto Ping Master and
#!/usr/bin/python
#coding: Utf-8
Import subprocess
def myping (x):
M=subprocess.call (' ping-c2-i0.5-w2 w%s &>/dev/null '%x,shell=true)
If m==0:
Print '%s is up '%x
Else
Print '%s is down '%x
ip=[' 176.121.205.%s '%i for I in xrange (1,100)] # #定义列表并赋值
For j in IP: # # #循环列表
Myping (j)
#################################################
Multi-process [each process, has its own memory]
Multithreading [Share a piece of memory]

Multi-threaded ping host faster than above
#!/usr/bin/python
#coding: Utf-8
Import threading
Import subprocess
def myping (x):
M=subprocess.call (' ping-c2%s &>/dev/null '%x,shell=true)
If m==0:
Print '%s is up '%x
Else
Print '%s is down '%x
ip=[' 176.121.205.%s '%i for I in Xrange (1,254)]
For-J in IP:
A=threading. Thread (Target=myping,args=[j])
A.start ()
#################################################
Execute commands with multi-threaded remote hosts
#!/usr/bin/python
#coding: Utf-8
Import Paramiko
Import threading
def myssh (x): # #定义函数
host = x # #远程的主机ip
SSH = Paramiko. Sshclient () # #开启客户端 assigning variables to SSH
Ssh.set_missing_host_key_policy (Paramiko. Autoaddpolicy ()) # #自动创建远程密钥
Ssh.connect (host,username= ' root ', password= ' Taren1 ') # #连接输入用户名密码
Ssh.exec_command (' mkdir/root/desktop/Go to this Tour ') # #远程执行命令
b=[' 176.121.205.%d '%i for I in Xrange (23,60)] # #利用for循环创建列表
For j in B: # #利用for循环取出列表, take one loop at a time
A=threading. Thread (Target=myssh,args=[j])
A.start ()

Regular expressions

Python errors and exceptions, re-modules, multi-threading, Paramiko modules