Shell echo命令:输出字符串

 
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。请看下面的例子:
#!/bin/bash

name="Shell教程"
url="http://c.biancheng.net/shell/"

echo "读者,你好!"  #直接输出字符串
echo $url  #输出变量
echo "${name}的网址是:${url}"  #双引号包围的字符串中可以解析变量
echo '${name}的网址是:${url}'  #单引号包围的字符串中不能解析变量
运行结果:

读者,你好!
http://c.biancheng.net/shell/
Shell教程的网址是:http://c.biancheng.net/shell/
${name}的网址是:${url}

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!"
运行结果:

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

我们可以添加-e参数来让 echo 命令解析转义字符。例如:

[root@localhost ~]# echo -e "hello \nworld"
hello
world

\c 转义字符

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。请看下面的例子:
#!/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!"
运行结果:

Tom is 20 years old, 175cm in height and 62kg in weight.
Thank you!