-n：不自动换行
[root@localhost ~]# echo -n "good noon\c"
good noon\c[root@localhost ~]#
-E：（默认）不支持\解释功能
[root@localhost ~]# echo "good noon\c"
good noon\c
[root@localhost ~]# echo -E "good noon\c"
good noon\c
-e：启用\解释功能
[root@localhost ~]# echo -e "good noon\c"
good noon[root@localhost ~]#
\a 发出警告声
\b 退格键
\c 最后不加上换行符号
\n 换行且光标移至行首
\r 回车，即光标移至行首，但不换行
\t 插入tab
\\插入\字符
\0nnn 插入nnn（八进制）所代表的ASCII字符
echo -e '\033[43;31;5mmagedu\033[0m'
\xHH插入HH（十六进制）所代表的ASCII字
[root@localhost ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/root/bin
[root@localhost ~]# echo echo $PATH
echo /usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/root/bin
双引向(变量可以，命令不行)：“”----弱引用：可以解释变量，命令不行
[root@localhost ~]# echo "echo $PATH"
echo /usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/root/bin
单引向（命令和变量都不可以）：‘’-----强引用：不解释包含的命令与变量，直接原本输出
[root@localhost ~]# echo 'echo $PATH'
echo $PATH
反引向（命令和变量都可以）：··=$()（键盘~键）------引用:直接将内容当成命令(第1个为命令，后面为选项、参数)
[root@localhost ~]# echo `echo $PATH`
/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/root/bin
[root@localhost ~]# echo $(echo $PATH)
/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/root/bin
大括号：｛｝：分组（可用符号“..”;","等等）
[root@localhost ~]# echo {1..10}
1 2 3 4 5 6 7 8 9 10
[root@localhost ~]# cd /app
[root@localhost app]# touch f{1..10}
[root@localhost app]# ls
f1 f10 f2 f3 f4 f5 f6 f7 f8 f9
[root@localhost app]# touch f{1..10}.{log.txt}
[root@localhost app]# ls
f10.{log.txt} f2.{log.txt} f4.{log.txt} f6.{log.txt} f8.{log.txt}
f1.{log.txt} f3.{log.txt} f5.{log.txt} f7.{log.txt} f9.{log.txt}
[root@localhost app]# rm -rf ./*
[root@localhost app]# touch f{1..10}.{log,txt}
[root@localhost app]# ls
f10.log f1.log f2.log f3.log f4.log f5.log f6.log f7.log f8.log f9.log
f10.txt f1.txt f2.txt f3.txt f4.txt f5.txt f6.txt f7.txt f8.txt f9.txt
特例：用于备份cp f1{,.bak}(首先要有f1文件)
[root@localhost app]# ls
[root@localhost app]# cp f1{,.bak}
cp: cannot stat ‘f1’: No such file or directory
[root@localhost app]# touch f1
[root@localhost app]# cp f1{,.bak}
[root@localhost app]# ls
f1 f1.bak
步进：{1..10..2}
[root@localhost app]# echo {1..10..2}
1 3 5 7 9
