[-A file] is true if file exists.[-B file] True if file exists and is a block special file.[-C file] True if file exists and is a word special.[-D file] True if file exists and is a directory.[-E File] True if file exists.[-F file] True if file
If statement format:If condition then statements [elif condition then statements ...] [Else statements] fiThe syntax for the most streamlined if command is:if TEST-COMMANDS; then CONSEQUENT-COMMANDS; fiThe IF condition judgment statement
This article mainly introduced the shell script if condition judgment and the judgment condition summary, this article first gave the IF condition judgment the grammar, then gave the commonly used judgment condition summary, needs Friend can refer
The shell condition determines if the-Z to-D meaningShellfilestringless Terminal user[-A file] is true if file exists.[-B file] True if file exists and is a block special file.[-C file] True if file exists and is a word special.[-D file] True if
From: http://m.jb51.net/article/56553.htm This article mainly introduced the shell script if condition judgment and the judgment condition summary, this article first gave the IF condition judgment the grammar, then gave the commonly used judgment
[-A file] is true if file exists.[-B file] True if file exists and is a block special file.[-C file] True if file exists and is a word special.[-D file] True if file exists and is a directory.[-E File] True if file exists.[-F file] True if file
by Francis_hao Oct 1,2017This article extracts the Man Handbook from bashConditional expressionsThe conditional expression is composed of a composite command [[or] built-in command test and [used for testing file properties and string or numeric
[ -a file] is true if file exists. [ -b file] True if file exists and is a block special file. [ -c file] True if file exists and is a word special. [ -d file] True if file exists and is a directory. [ -e file] is true if file exists. [ -f file]
1. String judgmentSTR1 = str2 When two strings have the same content, length is trueStr1! = str2 True when string str1 and str2 are not equal-N str1 True when the length of the string is greater than 0 (string non-null)-Z str1 True when the string
The shell condition determines if the-Z to-D meaning[-A file] is true if file exists.[-B file] True if file exists and is a block special file.[-C file] True if file exists and is a word special.[-D file] True if file exists and is a directory.[-E
[-A file] is true if file exists.[-B file] True if file exists and is a block special file.[-C file] True if file exists and is a word special.[-D file] True if file exists and is a directory.[-E File] True if file exists.[-F file] True if file
Objective:No matter what programming language is inseparable from conditional judgment. The shell is no exception.Copy CodeThe code is as follows:If List ThenDo something hereElif List ThenDo another thing hereElseDo something else hereFiEX1:Copy
Writing the first shell scriptLike other languages, we use any kind of text editor, such as Nedit, Kedit, emacs, vi, etc. to write our shell program. The program must start with the following line (must be in the first line of the file):#!/bin/shThe
1. string Judgments
STR1 = str2
True when two strings have the same content, length
Str1! = str2
True when strings str1 and str2 are unequal
-N str1
True when the length of a string is
Xi. functionsThe shell function is defined by the description of the shell grammar above and holds a series of commands waiting to be executed later. When the shell function name is used as a simple command name, a series of commands associated with
(a) Conditions to determine if the meaning of-Z to-D[-A file] is true if file exists.[-B file] True if file exists and is a block special file.[-C file] True if file exists and is a special file of a word . [-D file] True if file exists and is a
If condition judgment1. Basic syntax:if [command]; ThenStatements that meet the criteria for executionFi2. Extended syntax:if [command];thenStatements that meet the criteria for executionelif [Command];thenStatements that meet the criteria for
Http://wenku.baidu.com/link?url=9Q9VU54XuvlN77urP1zwOLVMMrS2EFNx4HcvFizdPl-zQy3K_ Ipd3o-mdu4sbihezumnq0blbwhusuaol_y6quvkxtgjiaem9gq9i-jb5_e Shell in the condition to determine if in the-Z to-D meaning 2011-09-05 [-a file] if the file The existence
first, the numerical judgmentInt1-eq INT2 INT1 and INT2 two number equal true Int1-ne INT2 INT1 and INT2 two number of true int1-gt INT2 INT1 greater than INT1 for true int1-g e INT2 INT1 greater than or equal to INT2 trueInt1-lt INT2 INT1 Less than
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