Shell

When it comes to sockets, people who have learned the basics of internet have heard that he is the abstraction of TCP/IP, he is the portal of the Internet world, it is everywhere. Learn the socket programming, means to be able to more deep control

Array Assignment: A= (1 2 3 4 5)A[1]=1 Array length: Echo ${#a [@]} or echo ${#a [*]} Read array: Echo ${a[@]} or Echo ${a[*]}echo ${a[0]} PS: array subscript starting from 0Delete array: unset aUnset A[1]Array fragmentation: Echo ${a[@]:0:3}

This article collects a bunch of shell scripting tricks, I said, I write a blog mainly to make some learning notes to facilitate their own review, so I will make such an article, there is nothing incomprehensible. About the origin of these

Learn awk, you must remember to practice, only in practice to find problems, the following on my experience in learning and practice, summed up the difference between rs,ors,fs,ofs and contact. One, RS and ors 1,rs is the record delimiter , the

The shell getopts and getopt usage 1.getoptsgetopts (shell built-in command) cannot directly handle long options (such as:--prefix=/home, etc.), Getopts has two parameters, the first parameter is a string, including characters and ":", each

The function of the DF command in Inux is used to check the disk space usage of the Linux server's file system. You can use this command to get information about how much space the hard disk is taking up, and how much space is left.1. Command

Execute shell command in PythonThe previous execution of the shell command is mostly done by Os.system (Shell command), which is more cumbersome.Understand that SH is a better library than subprocess, capable of executing shell commands1. View

Take Hadoop 2.7.3 as an exampleThe bin directory is the most basic cluster management script that allows users to perform various functions, such as HDFS management, MapReduce job management, and so on.As a primer, first describe how Hadoop scripts

This article explains the numerical calculation of variables in shell programming.1. Common Arithmetic operators:650) this.width=650; "Width=" "height=" 216 "title=" 2.png "style=" WIDTH:600PX;HEIGHT:216PX; "alt=" Wkiom1j4rnrydwfjaabg6obovmq759.png "

In a structured command, the most basic type is the If-then statement if Commandthen Commandfibash the Shell's if statement executes the IF line definition of the command, and if the exit status code of the command is 0, then the command in the then

#ifelse_exam. Sh script is used to check whether the input string is a current directory #!/bin/bash# test user input is empty, and then determine if the current directory exists for the file if ["$"]then echo "what are        NOT NULL "if [-E" $ "]

Rman backup is easy to use and inexpensive for Oracle database backup and recovery. For non-catalog mode, it is undoubtedly the first choice to embed Rman scripts into shell scripts and then use crontab to make small database database backups. This

Enterprise Utility Script 16Enterprise Case: Write Network Service standalone process mode rsync system startup scriptFor example:/etc/init.d/rsyncd{start|stop|restart}.Requirements:1. To use the System function library technique.2. To use a

Recent continuous integration with jenkins+gitlab+ansible, automated deployment and version rollback. However, the Deploy plugin failed to do incremental upgrades and rollback operations, tossing a long time to decide to write their own script

The meaning of several variables in a common shell with a $ symbol:Difference:@">@ * Same point: All parameters are referenced Different points: only in double quotes. Suppose that three parameters were written when the script was run (stored

One, shell condition Test man bash//view HelpCommands for conditional testsTest option file name or directory nameOr[option file name or directory name]Cases:[-E/ETC/PASSD]File status-F//judgment is not a file, is the file is True- D//Determine if

Q: What is a shell and what is a shell script?A:shell is a program written in C, which is a bridge between the user and the Linux operating system. The user can either enter command execution or use shell scripting to do more complicated operations.

The old boy Yun-dimensional class 25-26 period, nearly 350 students, about to accept the Shell Advanced Programming Course baptism, first give everyone to a scare topic it!Tips:Prohibit any search, self-suppressed is the hero!Search for a meeting,

Variable Description:   $$ the PID of the shell itself (ProcessID)   $! PID of the Shell's last running background process   $? end code of the last Run command (return value)   $- flag at a glance using the SET command   $* all parameter

Debug is more boring, so here first on the conclusions and examples, Debug notes do not look and no confusion.ConclusionUsing the return value in the shell, the only way to be universal is to use a global variable, or use Echo and receive it in the