Hello everyone , I'm a junior
Today's article comes from a little trick at work , It mainly involves the automatic processing of daily work .
If you need to do some repetitive work every day , Like a report 、 Count a number 、 Send an email and so on
Then you can give this task to the computer and let it finish it automatically for you every day , And you just need to open the mug calmly , Soak a cup of wolfberry quietly
Today we will mainly use Linux Under the cron This service ,ok, Just start
1. install cron
Basically all Linux Distributions are pre installed by default cron Tools .
Even if not pre installed cron, It's also very simple. , Execute a few simple commands to manually install
# Check that it's pre installed cron service cron status
Install and start services
install ：apt-get install cron start-up / stop it / restart ：service cron start/stop/restart Query the current task ：crontab -l
2. Installation inspection
After installation, check whether the installation is successful , Also use status Command view
The following prompt indicates that the installation is successful ：
in addition , stay ubuntu There may be a hint like this ：
This also means it can be used normally
3. cron usage
There are a few about cron You can learn something about , In the following, we will introduce how to use
First , List the current user's planned cron Homework ：
View other users' cron Homework ：
crontab –l –u username
Remove planned cron Homework ：
4. Dispatch crontab plan
First , By the following order Add or update crontab The task
The first entry will ask you to select the editor , This is chosen according to your own habits .
After selection, you will enter such an interface ：
Used to vim You should be familiar with this interface , Similar operation ： Press A Key to start editing , Press ESC Input wq Save and exit
The point is the bottom paragraph ：
m h dom mon dow commmand
This is actually crontab An introduction to the use of scheduling jobs , It can be used to set scheduled tasks .
The more specific grammar is like this ：
m h dom mon dow command * * * * * command - - - - - - | | | | | | | | | | | --- Pre executed commands | | | | ----- Means week 0～7（ You can use it on Sunday 0 or 7 Express ） | | | ------- Represents the month 1～12 | | --------- Indicates the date 1～31 | ----------- For hours 1～23（0 Express 0 spot ） ------------- Represents minutes 1～59 Per minute * perhaps */1 Express
Here are some simple examples ：
- Every day 02:00 Perform tasks
0 2 * * * command
- Every day 5:00 and 17:00 Perform tasks
0 5,17 * * * command
- Every time 10min Perform a task
*/10 * * * * command
- On the Sunday of a particular month 17:00 Perform tasks
0 17 * jan,may,aug sun command
These are the most commonly used ones , More use cases can also refer to this link ：http://linux.51yip.com/search...
In the case above command The specific task you need to perform , For example, print a paragraph ：
echo "Hello xiaoyi" >> /tmp/test.txt
Or output this passage to txt in ：
echo "Hello xiaoyi" >> /tmp/test.txt
Or you need to execute a Python Script ：
python demo.py filepath
hinder filepath Represents the input parameter args, This may be used by some students , For example, in the following case, you need to enter the file download path .
5. actual combat
All of the above are clear , We can start today's play .
First of all, we need to start from ftp Download the latest task data from the server , Download the data to the local and then use Python Data collection and statistics , Finally, the results are stored in the database , If there is a problem in a certain link during the period, an alarm email will be sent .
① Python Script
The first thing you need to Python Scripts do the following ：
- Get the latest date from the database
- from ftp Download the latest data to local
- Collect and count the latest local data
- The statistical results are stored in the database for summary
- Mail notification
The pseudo code of the above process is like this ：
if __name__ == '__main__': """ Get the latest data date """ latest_date = get_max_date() # Create a folder with the name of the latest date download_dir = os.path.join(sys.argv, latest_date) if not os.path.exists(download_dir): os.makedirs(download_dir) """ from ftp Download the latest data from """ download_file(latest_date, download_dir) """ Process the latest data and save it """ process_data(latest_date, download_dir)
Email monitoring can add a try catch Exception capture , Send an email when there is an exception
Python Edit the content of the email and send it. I've written about it before , You can refer to the following ：Python Mail delivery
② To write cron Mission
open crontab, Edit the following to the last line , Save and exit
crontab It will automatically update the task list in real time , If you are not at ease, you can also go through restart Command restart cron service 【 Refer to the beginning of the article 】
Here's a tip , Fill in the absolute path for all paths
③ Effect monitoring
If Python There's no problem with the code , The task will be executed regularly .
Here we suggest that you can put your own command Running on the console alone , When there is no problem, write in cron Task list red .
Finally, the running screenshot of primary one's timing task is as follows ：
At the bottom is ftp File download , It's a summary of the data
Say something out of the question
If you have a lot of repetitive tasks in your daily work , Like the collection of daily indicators 、 Data retrieval, summary and statistics 、 Automatic mail forwarding, etc
Once this is done, you can set up the logic through the script , Automated tasks can do it , At most, you need to pay attention to your email every day , Just see if there are any mistakes .
Originality is not easy. , Welcome to like
The article first ： official account 【 Zhiqiu Xiaoyi 】
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