# 4. 变量与参数

### 本章目录

* [4.1 变量替换](/advanced-bash-scripting-guide-in-chinese/zheng-wen/part2/04_introduction_to_variables_and_parameters/04_1_variable_substitution.md)
* [4.2 变量赋值](/advanced-bash-scripting-guide-in-chinese/zheng-wen/part2/04_introduction_to_variables_and_parameters/04_2_variable_assignment.md)
* [4.3 Bash变量弱类型](/advanced-bash-scripting-guide-in-chinese/zheng-wen/part2/04_introduction_to_variables_and_parameters/04_3_bash_variables_are_untyped.md)
* [4.4 特殊变量类型](/advanced-bash-scripting-guide-in-chinese/zheng-wen/part2/04_introduction_to_variables_and_parameters/04_4_special_variable_types.md)

变量（variable）在编程语言中用来表示数据。它本身只是一个标记，指向数据在计算机内存中的一个或一组地址。

变量通常出现在算术运算，数量操作及字符串解析中。


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