括号扩展：{ }
{} 可以实现打印重复字符串的简化形式
[10:04:14 root@C8[ 2020-06-16DIR]#echo file{1,3,5}
file1 file3 file5
[10:11:58 root@C8[ 2020-06-16DIR]#echo {1..35}
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35
[10:12:22 root@C8[ 2020-06-16DIR]#echo {a..z}
a b c d e f g h i j k l m n o p q r s t u v w x y z
[10:12:34 root@C8[ 2020-06-16DIR]#echo {a..Z} #ASSCII码
a ` _ ^ ] [ Z
[10:12:40 root@C8[ 2020-06-16DIR]#echo {A..z}
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z [ ] ^ _ ` a b c d e f g h i j k l m n o p q r s t u v w x y z
[10:12:56 root@C8[ 2020-06-16DIR]#echo {1..36..2}
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35
[10:13:35 root@C8[ 2020-06-16DIR]#echo {1..36..3}
1 4 7 10 13 16 19 22 25 28 31 34
[10:13:45 root@C8[ 2020-06-16DIR]#echo {1..36..4}
1 5 9 13 17 21 25 29 33
[10:13:49 root@C8[ 2020-06-16DIR]#echo {1..36..5}
1 6 11 16 21 26 31 36
[10:13:52 root@C8[ 2020-06-16DIR]#echo {1..36..6}
1 7 13 19 25 31
[10:13:55 root@C8[ 2020-06-16DIR]#echo {1..36..7}
1 8 15 22 29 36
[10:13:58 root@C8[ 2020-06-16DIR]#echo {1..36..10}
1 11 21 31
可以组合使用
笛卡尔乘积 完全组合
[10:14:03 root@C8[ 2020-06-16DIR]#echo file{1..10}.{txt,log}
file1.txt file1.log file2.txt file2.log file3.txt file3.log file4.txt file4.log file5.txt file5.log file6.txt file6.log file7.txt file7.log file8.txt file8.log file9.txt file9.log file10.txt file10.log
[10:21:26 root@C8[ 2020-06-16DIR]#echo {20200601..20200616}.log #生成20200601到20200616的日志文件
20200601.log 20200602.log 20200603.log 20200604.log 20200605.log 20200606.log 20200607.log 20200608.log 20200609.log 20200610.log 20200611.log 20200612.log 20200613.log 20200614.log 20200615.log 20200616.log