echo在linux里是一个用于字符串输出的命令；echo命令的语法是“echo [-neE] [arg ...]”，其中参数“-n”表示输出字符串不换行，参数“-e”表示对于转义字符按对应的方式进行处理，参数“-E”表示禁用转义解释。
本教程操作环境：linux5.9.8系统、Dell G3电脑。
echo在linux里是什么意思？
linux命令：echo
Shell中的echo命令类似于php中的echo命令，都是用于输出。Shell中另有一个输出命令为printf命令。
本文中的一系列实例用到的命令我都是在终端直接写的，输出也是输出在终端，这样方便学习和记录吧！其实也都可以放到脚本文件中执行。
一、语法
echo [-neE] [arg ...]
（1）含义-n:表示输出字符串不换行-e:表示对于转义字符按对应的方式进行处理（若不加-e ，那么在输出时转义字符会按照普通字符进行处理，并不会达到自己想要达到的目的。）-E:禁用转义解释
| 转义字符 | 含义 |
|---|---|
| \b | 删除前一个字符 |
| \n | 换行 |
| \t | 水平制表符（tab） |
| \v | 垂直制表符（tab） |
| \c | \c后面的字符将不会输出，输出完毕后也不会换行 |
| \r | 光标移动到首行，不换行 |
| \f | 换行，光标停在原处 |
| \e | 删除后一个字符 |
| \ | 输出\ |
| \0nnn | 输出八进制nnn代表的ASCII字符 |
| \xHH | 输出十六进制数HH代表的ASCII字符 |
| \a | 输出一个警告的声音 |
（2）实例
[root@localhost my_shell]# echo "hello "hello [root@localhost my_shell]# echo -n "hello "hello [root@localhost my_shell]# echo "hello \b"hello \b[root@localhost my_shell]# echo -e "hello \b"hello [root@localhost my_shell]# echo -en "hello \b"hello[root@localhost my_shell]# echo -e "hello\tworld"hello world[root@localhost my_shell]# echo -e "hello\nworld"hello world[root@localhost my_shell]# echo -e "hello\vworld"hello world[root@localhost my_shell]# echo -e "hello\cworld"hello[root@localhost my_shell]# echo -e "hello\rworld"world[root@localhost my_shell]# echo -e "hello\aworld"helloworld[root@localhost my_shell]# echo -e "hello\cworld"hello[root@localhost my_shell]# echo -e "\ehelloworld"elloworld[root@localhost my_shell]# echo -e "hello\\world"hello\world[root@localhost my_shell]# echo -e "\x31"1[root@localhost my_shell]# echo -e "\0123"S
（3）具体用法
上面介绍的主要是一些输出字符串相关的具体用法，下面详细例举一些echo命令的其他用法。
1、显示普通字符串
[root@localhost ~]# echo "hello world"hello world[root@localhost ~]# echo hello worldhello world#双引号可以省略，效果一致。（字符串的输出都是如此，下面一些实例也是可以省略双引号也能达到相同效果）
2、显示变量
这里用到read命令（从标准输入中读取一行,并把输入行的每个字段的值指定给 shell 变量）。
[root@localhost ~]# read nameMichael Zhang[root@localhost ~]# echo "My name is $name"My name is Michael Zhang
3、显示换行
[root@localhost ~]# echo -e "hello \nworld"hello world
4、显示不换行
#!/bin/shecho -e "OK! \c" # -e 开启转义 \c 不换行echo "hello world"#结果如下OK! hello world
5、显示转义字符
[root@localhost ~]# echo "\"hello world\"""hello world"
6、重定向
结果输出到文件
echo "hello world" > my_file#将hello world输出到my_file文件
7、原样输出
用单引号可原样输出。
[root@localhost ~]# echo '$name\"'$name\"[root@localhost ~]# echo '$name'$name
8、显示命令执行结果
#显示当前日期[root@localhost ~]# echo `date`Sat Jan 2 23:12:39 CST 2021
这里使用的是反引号`, 而不是单引号’。
实际上输出一些执行命令的结果就是这样用反引号。
二、echo的重定向
重定向是Shell中的一个重要内容。
echo命令的重定向功能经常被用于清空文件内容（删除文件）时使用
（1）echo "content" > filename
将content覆盖到filename文件当中去，filename文件当中之前的内容不复存在了，实际上是修改了原文件的内容。
（2）echo "content" >> filename
将content追加到filename文件后，对filename文件之前的内容不修改，只进行增添，也叫追加重定向。
（3）实例
[root@localhost my_shell]# touch test[root@localhost my_shell]# cat test [root@localhost my_shell]# lltotal 4-rw-r--r-- 1 root root 175 Nov 6 17:46 del.sh -rw-r--r-- 1 root root 0 Nov 7 23:33 test[root@localhost my_shell]# echo "123456" > test[root@localhost my_shell]# cat test123456[root@localhost my_shell]# echo "111111" > test[root@localhost my_shell]# cat test111111[root@localhost my_shell]# echo "123456" >> test[root@localhost my_shell]# cat test111111123456[root@localhost my_shell]#
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