exit status

Python process Programming 1. There are two ways to achieve concurrency, one is to let each "task" or "process" work in a separate internal space, each with its own working memory area. However, although processes can be executed in a separate

Shell BASICS (II)-shell variables, basics-shell 1. Define Variables 1) when defining a variable, the variable name does not contain the dollar sign ($), for example:Var = "hello world"2) Note that there is no space between the variable name and

File test:-e file: Test files exist-F File: Test files are normal files-D File: Tests whether the specified path is a path-R File: Tests whether the current user has read access to the specified file-W File: Tests whether the current user has write

main function and start routineWhen the kernel executes a C program using an EXEC function, a special startup routine is called before the main function is called, and the executable program designates this routine as the starting address of the

getopts CommandUseProcesses command-line arguments and verifies valid options.Grammargetopts option string name [parameters ...]DescribeGetopts is designed to run in a loop, and each time a loop is executed, getopts checks the next command-line

Process exitThe process end indicates that the process is about to end, and the process exit methods in the Linux system are divided into normal exit and exception exit.Exit functionThe process has three normal termination methods and two kinds of

Summary of this chapterVariables are a must in a very small program . The shell variable retains the string value , and a large number of operators can be ${var ...} used in , let you control the result of the variable .Shellprovides a number of

Fundamentals of the ten-year OPS series-LinuxZeng LinContact: [Email protected]Website: www.jplatformx.comCopyright: Please do not reprint the article without permission first, use the IF statementThrough the shell, we can write a shell script

Description in Unix, all processes except process 0 (that is, the pid=0 exchange process, swapper process) are created by other processes using the system call fork, where the process called fork creates a new process is the parent process, and the

One, parenthesis, round brackets () 1, single parenthesis () ① command group. The commands in parentheses will be executed in a new sub-shell sequence, so the variables in parentheses cannot be used by the rest of the script.   Multiple commands in

One, parenthesis, round brackets () 1, single parenthesis () ① command group. The commands in parentheses will be executed in a new sub-shell sequence, so the variables in parentheses cannot be used by the rest of the script.　　Multiple commands in

the parentheses are the orders. curly braces are variable valuesOne, parenthesis, parentheses ()1 , single parenthesis ()① Command Group. The commands in parentheses will be executed in a new sub-shell sequence, so the variables in parentheses

One, parenthesis, round brackets () 1, single parenthesis () ① command group. The commands in parentheses will be executed in a new sub-shell sequence, so the variables in parentheses cannot be used by the rest of the script.   Multiple commands in

1.break jump out of the code snippet to end this loop2.continue ends the current clip, ends the cycle, and continues the next cycle3.exit end of entire PHP codeThe function of break is to jump out of this loop (if this break or continue inside the

First question: For the installation process requires Super permissions, and LTIB installation is not allowed to use root user installation, so only modify/etc/sudoers file, sudo visudo Add username all=nopasswd on the last

1. Shell Introduction 1.1 Shell appearance backgroundThe Shell is both a scripting language and a software for connecting cores and users.For the graphical interface, the user can start a program by tapping an icon, and for the command line, the

One, parenthesis, round brackets () 1, single parenthesis () The command group . The commands in parentheses will be executed in a new sub-shell sequence, so the variables in parentheses cannot be used by the rest of the script. Multiple

VariableA variable is a named memory spaceAll variables in the shell are treated as character variables by default, and bash does not support floating-point variablesNaming rules for variables:You cannot make a reserved word in a program: for

Compile-language:The program needs a special compilation process before execution, which compiles the program into a machine language file, the runtime does not need to be re-translated, the results of the direct use of the compilation is OK. The

2016-08-18Content of the lesson:Shell Programming Basics (select loops and menus, functions)Yum Management, custom Yum WarehouseSelect loops and MenusSelect variable in listDoCircular Body CommandDone1. The Select loop is used primarily to create