bash programming book

Conditional Judgment of Bash programmingBash Programming condition judgment: determine if the prerequisites for subsequent operations are met　　　　　　　　　　1. The common judgment type of condition judgment (bash endogenous):Integer testCharacter testFile test2. Echo $? (Execution status return value): 0: correct 1-255: Error br> True or false 3, logical o

Problems encountered in Bash programming:First, it is recommended that you write bash under Linux, and if you want to write bash with Windows, you should pay special attention to several issues:First: Coding problems, encoded with utf-8,Second: line break problem, Windows is the end of carriage return (CRLF), Linux is the end of line break (LF)Third: Use Utf-8 wi

: Instruction + datadirective: Provided by Program FilesData: IO devices, files, pipelines, variables?Program: algorithm + data structure?Variable name + point to memory space?Variable assignment: Name=valueVariable types: Storing formats, representing data ranges, participating operations? ? Programming Languages:? ? ? ? ? ? Strongly typed variables? ? ? ? ? ? Weakly typed variables:And?????????? Bash all

Bash (GNU Bourne-again Shell) is a Unix shell written for the GNU program, which is the default shell used by many Linux platforms.Variables for bash scripting:1. $BASHRepresents the path of a bash binary program fileEg: Edit the bash file, such as 1.sh, in which the following code is entered:Then save the run and the

usage of the while loop:Traverse each line of the file:while read VARIABLE; DoLoop bodyDone Example: Find all users whose UID is even, display their user name and ID number;#!/bin/bash#while read line;douserid=$ (echo $line | cut-d:-F3) If [$[$userid%2]-eq 0];then echo $line | Cut-d:-f1,3fidone Special usage for the FOR loop:For ((EXPR1;EXPR2;EXPR3)); DoLoop bodyDoneEXPR1: Defines the control variable and assigns the initial value;EXPR2: cyclic contr

lock mail opt run tmp ypcache CVS empty GDM local lo G NIS Preserve spool www# inittab is only used by upstart forThe default runlevel.## ADDING Other CONFIGURATION here would have NO EFFECT on YOUR system.## SYSTEM initialization i S started by/etc/init/rcs.conf## Individual runlevels is started by/etc/init/rc.conf## Ctrl-alt-delete is handled by/etc/init/control-alt-delete.conf## Terminal Gettys is handled by/etc/init/tty.conf and/etc/init/serial.conf,# with configurationinch/etc/sysconfig/in

Linux: In bash programming, the circular statement usage 1.if is a single branch statement in the following format: if condition; then statement ..... Fi 2.if... Else is a dual-branch statement in the following format: if condition; then statement .... Else statement .... Fi 3.if... Elif... Elif... Else is a multi-branch statement in the following format: if condition; then statement .... Elif condition; th

programs like the C programming language.There are many different shells in Linux, but usually we use Bash (Bourne again shell) for Shell programming because bash is free and easy to use. A shell script file starts with #!/bin/bash, and the comment begins with #.Here are a

Linux programming-Bash variables-general Linux technology-Linux programming and kernel information. The following is a detailed description. 1. User-Defined variables A user-defined variable consists of letters, numbers, and underscores. the first character of the variable name cannot be a number. Like other UNIX names, variable names are case sensitive. You can

this user, and green display;4, the final display altogether added several users;#!/bin/bash#Declare-i usercount=0For i in {1..10}; DoIf ID stu$i >/dev/null; ThenEcho-e "\033[31mstu$i\033[0m exists."ElseUseradd stu$i echo-e "Add \033[32mstu$i\033[0m finished."Let usercount++FiDoneecho "Add $userCount users."For: By using a variable to traverse each element in a given list, the loop body is executed once each time the variable is assigned, until the

The Bash shell script programming knowledge points are as follows (beginner, incomplete, welcome to the discussion supplement):Shell IntroductionA simple introduction to scriptsVariables and referencesArithmetic operationsInteractive programmingSelect JudgmentCondition testCycleFunctionShell IntroductionShell is a special function of the program, provides a user to interact with the kernel interface, it rec

Bash Script Programming:???? Scripting: Interpreter interpretation execution; first of all have to clear up some trivial knowledge points, I try to do what I learned to help friends comb Programming Environment: (I will be in the next chapter, graphic examples three combinations way to take everyone to study together)???????????? Process Contro

The definition format of the 1:bash function [Function] funname [()]{action; [return int;]}Description1: Can be defined with function fun () or directly fun (), without any parameters.2: The function returns a value that can be returned with a return, or, if not, the result of the execution of the last line of the function body as the return value. Return followed by a value of 0-255. After calling the function, the return value is obtained by $