echo 是一个 Shell 内建命令，用来在终端输出字符串，并在最后默认加上换行符。
输出不换行
echo 命令输出结束后默认会换行，如果不希望换行，可以加上-n参数，如下所示：
#!/bin/bash
name="Tom"
age=20
height=175
weight=62
echo -n "${name} is ${age} years old, "
echo -n "${height}cm in height "
echo "and ${weight}kg in weight."
echo "Thank you!"
输出：
Tom is 20 years old, 175cm in height and 62kg in weight.
Thank you!
输出转义字符
默认情况下，echo 不会解析以反斜杠\开头的转义字符。比如，\n表示换行，echo 默认会将它作为普通字符对待。请看下面的例子：
[root@localhost ~]# echo "hello \nworld"
hello \nworld
参数：-e
我们可以添加-e参数来让 echo 命令解析转义字符
[root@localhost ~]# echo -e "hello \nworld"
hello
world
转义字符：\c
有了-e参数，我们也可以使用转义字符\c来强制 echo 命令不换行了
#!/bin/bash
name="Tom"
age=20
height=175
weight=62
echo -e "${name} is ${age} years old, \c"
echo -e "${height}cm in height \c"
echo "and ${weight}kg in weight."
echo "Thank you!"
输出：
Tom is 20 years old, 175cm in height and 62kg in weight.
Thank you!