选项作为 Bash 中declare命令的一般参数 declare内置命令接受以下选项作为通用参数: $ bash -c"help declare" 输出: declare: declare [-aAfFgilnrtux] [-p] [name[=value] ...]Set variable values and attributes.Declare variables and give them attributes. If no NAMEs are given,display the attributes ...
A variable in bash is created by assigning a value to its reference. Although the built-indeclarestatement does not need to be used to explicitly declare a variable in bash, the command is often employed for more advanced variable management tasks. This tutorial will show you how to work wit...
[root@PC1 dir1]# echo $var1 [root@PC1 dir1]# declare-r var1## 定义变量为只读[root@PC1 dir1]# var1=100-bash: var1:readonlyvariable [root@PC1 dir1]# var1="hello world"-bash: var1:readonlyvariable [root@PC1 dir1]# var1=hello_word-bash: var1:readonlyvariable [root@PC1 ...
-bash: r: readonly variable [root@jfht ~]#declare -r r=xxx -bash: declare: r: readonly variable [root@jfht ~]#declare +r r -bash: declare: r: readonly variable [root@jfht ~]# [root@jfht ~]#declare +r r -bash: declare: r: readonly variable [root@jfht ~]# [root@jfht...
在Linux Shell中,declare命令是作为一个内建命令(built-in command)实现的,也就是说它是由Shell解释器直接处理的,而不是通过外部的可执行文件来执行。 底层实现的具体细节取决于所使用的Shell解释器。在Bash Shell中,declare命令的底层实现是通过Shell解释器内部的函数来完成的。当Shell解释器遇到declare命令时,它会调用...
var1=2367.1 # Results in error message, with no change to variable. echo "var1 is still $var1" echo declare -r var2=13.36 # 'declare' permits setting a variable property #+ and simultaneously assigning it a value. echo "var2 declared as $var2" # Attempt to change readonly variable...
1. Basic Usage of declare Command in Bash 1.1. Define a Variable Thedeclarecommand is often used to define variables with specific attributes. declare my_var="Hello, World!" echo "$my_var" Declaring a Variable This works the same as a normal variable assignment (my_var="Hello, World!")...
bash 中 `declare -p <variable>` 的输出是否保证可重用为 shell 输入? 这是专门关于bash的- 在这个答案declare中对一般情况进行了非常详尽的处理(其中提到“ // , ,的输出”,但没有提到的输出)。typesetdeclareexport -pksh93mkshzshbash 给定一个本地/导出/数组/关联数组(但可能不是 nameref)变量...
purpleEndurer @ bash $help declare declare: declare [-aAfFgilrtux] [-p] [name[=value] ...] Set variable values and attributes. Declare variables and give them attributes. If no NAMEs are given, display the attributes and values of all variables. ...
$ declare -r foo $ echo $foo 123 $ foo=456 -bash: foo: readonly variable 1 2 3 4 5-l 赋给变量的值,所有大写字符都将转换为小写。 大写属性被禁用。 -u 赋给变量的值,所有小写字符都将转换为大写。 小写属性被禁用。 -n 给变量提供nameref属性,使其成为对另一个变量的引用。