Python module-command and sys

1.commands Module

A module for supporting the shell in a Linux system environment

1) getoutput ()

Return value only returns the result (string type), no way to determine whether the execution of the result is normal

Example

Import commands

cmd = "Ls/data/temp"

RESULT1 = commands.getoutput (cmd)

Print (type(RESULT1)) # type is str

Print (RESULT1)

Results:

<type ' str ' >

2.py

2) Getstatusoutout ()

The returned result is a tuple tuple, the first value is the receive status code, the int type, 0 for normal, not 0 for the exception, and the second value as a string, the result of the shell command execution

Example

Import commands

cmd = "Ps-ef"

STATUS,RESULT2 = commands.getstatusoutput (cmd)

Print (type(status))

Print (status)

Print (type(RESULT2))

Print (RESULT2)

Results:

<type ' int ' >

0

<type ' str ' >

UID PID PPID C stime TTY time CMD

Root 1 0 0 Oct09? 00:00:14/USR/LIB/SYSTEMD/SYSTEMD--switched-root--system--deserialize 21

Root 2 0 0 Oct09? 00:00:00 [Kthreadd]

2.sys Module

1) Get program parameters through SYS module

sys.argv[0]: The first argument, the script itself

sys.argv[1]: The second argument, the first parameter passed in

Example

import sys

print ( "argv[0]={0}   Argv[1]={1}" .format (sys.argv[ 0 ],SYS.ARGV [ 1

Results:

argv[0]=c:/users/test/pycharmprojects/a/a1.python.py argv[1]=parameter1

2) Sys.stdin,sys. STDOUT,sys. StdErr

The stdin, stdout, and stderr variables contain stream objects that correspond to standard I/O streams. If you need more control over the output, and print does not meet your requirements, you can also replace them, redirect output and input to other devices, or process them in a non-standard way

Example 1:sys.stdout and Print

import sys

sys.stdout.write ( "Hello" + " \n "

Print ("Hello")

Results:

Hello

Hello

Example 2:Sys.stdin and Raw_input

Import SYS

name1 = Raw_input ("Input your Name:")

Print (name1)

Print ' stdin_your_name: ' ,         # command to stay on the same line

name2 = Sys.stdin.readline () [:-1] #-1 to discard the ' \ n ' in input stream

Print (name2)

Results:

Input your NAME:HUANGZP

Huangzp

Stdin_your_name:huangzp

Huangzp

Example 3: Console redirection file

Import SYS

F_hander = Open ("Out.log","W")

Sys.stdout = F_hander

Print ("Hello")

Results:

Generates a Out.log file locally with the content Hello

3) Capture sys.exit (n) called

Executes to the end of the main program, the interpreter automatically exits, but if you want to exit the program halfway, you can call the Sys.exit function, with an optional integer parameter returned to the program that called it, indicating that you can capture the call to Sys.exit in the main program. (0 is normal exit, others are abnormal)

Example

Import SYS

def Exitfunc ():

print "Hello World"

Sys.exitfunc = Exitfunc # Set the function called when capturing

Print "Start"

sys.exit ( Span style= "Font-size:12px;font-family:simsun, Stsong;color:rgb (0,0,255); Background-color:rgb (255,255,255);" >1 )               # Exit Automatic call e xitfunc (), the program exits

Print "End" # does not execute print

Results:

Start

Hello World

Description

The Sys.exitfunc function is set and the Exitfunc function is called when the Sys.exit (1) is executed, and the contents of Sys.exit (1) are not executed because the program has exited

Python module-command and sys