文章来源： (linux shell)第一章--小试牛刀(下)

1.6 数组和关联数组

1.6.1 预备知识

Bash同时支持普通数组和关联数组，普通数组只能使用整数作为数组索引，而关联数组可以使用字符串作为数组索引。关联数组在很多操作中相当有用。

1.6.2 实战演练

定义数组的方法有很多，可以在单行中使用一列值来定义一个数组：

array_var=(1,2,3,4,5,6) #这些值将会存储在以0为起始索引的连续位置上

另外，还可以将数组定义成一组索引-值:

array_var[0]="test1"

array_var[1]="test2"

打印出特定数组元素的内容：

echo ${array_var[0]}

以清单形式打印出数组中的所有值：

echo ${array_var[*]}

打印数组长度

echo ${#array_var[*]}

1.7 使用别名

1.7.1 预备知识

别名有多种便捷方式，可以使用函数，也可以使用alias命令

1.7.2 实战演练

alias new_command='command sequence'

alias install='sudo apt-get install'

当然，这样修改的别名只是暂时的，只对当前终端有效，如果想一直保持作用，可将它放入~/.bashrc中

1.8 获取终端信息

1.8.1 预备只是

tput和stty是两款终端处理工具。

1.8.2 实战演练

获取终端的行数和列数

tput cols

tpu lines

打印出当前终端名称:<喎"http://www.2cto.com/kf/ware/vc/" target="_blank" class="keylink">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"Jan 20 2011' +%A

可以按照你的选择打印出日期格式：

date "+%d %B %Y"

时间的延时可以用sleep se╧y"http://www.2cto.com/kf/yidong/wp/" target="_blank" class="keylink">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"http://www.2cto.com/uploadfile/Collfiles/20140726/20140726090826107.png" title="2014-07-25-105420_485x126_scrot.png" alt="">

? ?字符串比较：

? ? ?可以检查两个字符串是否相等以及不相等：

? ? ?[[ $str1 = $str2 ]] [[ $str1 != $str2 ]]

? ? ?比较两个字符串之间的大小：

? ? ?[[ $str1 > $str2 ]] 或者 [[ $str1 < $str2 ]]

? ? ?[[ -z $str1 ]] 如果str1是空字符串，则返回真

? ? ?[[ -n $str1 ]] 如果str1是非空字符串，则返回真?