script if

Cases:[CPP]View PlainCopy Status = System ("./test.sh"); 1, first unified two statements: (1) System return value: Refers to the return value after invoking the system function, such as the status system return value (2) Shell return

Shell script is a "program" written using the shell's function, which uses plain text files to write some shell syntax and instructions (including external instructions), with regular expressions, pipeline commands, and data flow redirection. In

There is often a sentence at the beginning of a shell script to define what kind of SH interpreter to use to interpret the script.There are two main types of shell scripts that are currently developed for testing:(1) #!/bin/sh(2) #!/bin/bashWhat is

First to popularize a few knowledge: Everything under Linux is files, including input, network connections, sockets, pipelines, etc. The most relevant file opening number is the file descriptor (some people like to call the file

This article will aim to implement regular automatic backups of the MySQL database, and introduce the perfect collaborative process between shell scripts and scheduled tasks. Where the shell script is responsible for the specific backup operation,

When setting up timed tasks, you need to pay attention to a lot of details, such as permissions, paths, output logs, and so on, here in CentOS for example, give an example of successful implementation, but the actual set of methods, this article is

FunctionFunctions have the same functionality:Simply put, the function of the program is to call the same part of the code in a number of parts, and then a name, so the function is called the name can be, in the modification of the code, only need

(1) Write a script: If a path does not exist, it is created as a directory, otherwise it is present, and the content type is displayed#!/bin/bash#if [$#-lt 1]; Then echo "Plz Enter a path:" Exit 1fi if [-e $]; Then file $1else mkdir-p $1fi ~Test

The Magical magic of awk:Extract the number 600 and note the special effect of the + sign.echo "Fuck 600ms" |awk ' {print + $NF} 'Result: Other characters are filtered, leaving only the number 600Using If,for in Commad mode#测试ifa=200if [$a = =];then

Background: Based on the huge demand for visualizations and cost factors, using the Pyecharts + Django visualization is clearly a better choiceVisualize to find: patterns, relationships, and anomaliesEnvironment: People with obsessive-compulsive

Support for Arm64 FFmpeg under Mac compilationStarting in January 2015, Apple began to require all new AppStore applications to support arm64, and the previous ffmpeg would be rejected if it was not compiled to support the arm64 version. The

/etc/passwd and/etc/shadow in LinuxFirst,/etc/passwdThe/etc/passwd file is a plain text file with the same format for each line:Name:password:uid:gid:comment:home:shellName User Login NamePassword user password. Passwords in this domain are

use the If statement to determine parameters in Linux shell programming–b when file exists and is a block file returns true-D when file exists and is a character file returns True-e when pathname exists and is a directory returns true-F when a file

sed use syntax[Email protected] test]# sed--helpUsage: sed [options] ... {Script (if no other script)} [Input file] ...-N,--quiet,--silent Cancel auto Print mode space-e script,--expression= script adds "script" to the program's run list-F script

I use the system is: Redhat[Email protected] ~]# wget http://download.redis.io/releases/redis-2.8.12.tar.gzTar xzf redis-2.8.12.tar.gz[Email protected] ~]# tar xzf redis-2.8.12.tar.gz[Email protected] ~]# CD redis-2.8.12[[email protected] redis-2.8.1

Output debugging information in shell scripts is commonly used in the following ways:1.trap commandThe trap command is used to capture the specified signal and execute a pre-defined command. The basic syntax is: trap ' command ' signal. Where signal

Top10 is: Chocolatey It's a strange name, but it's a apt-get on Windows. Once you have it, you have nothing to ask for. (see: www.hanselman.com) Now I want to install the software, will first think of it rather than Google. I was just using '

Content Cache Output PEAR Cache Next we start to explore more commonly used caching techniques, which is also a key part of this article. First we use the cache package in pear. Pear can cache content in a file, in a database, or in memory, as an

The biggest advantage of using PHP for 1, code optimization Code optimization not only writes clean and clear code, but simplifies the code somewhat. You can use Zend Optimizer to help complete these miscellaneous tasks. Zend optimizer

Establish a database table maintenance specification It is a good idea to perform a database table check on a regular basis rather than waiting for the problem to occur. Consideration should be given to establishing a schedule of preventative