如何为read命令添加换行符?

 read -p "Please Enter a Message:" message

How can I add a line break after Message:?

如何在消息后添加换行符:?

7 个解决方案

#1

I like Huang F. Lei's answer, but if you don't like the literal line break, this works:

我喜欢黄f雷的答案，但如果你不喜欢文字的断行，这是可行的:

read -p "Please Enter a Message: `echo $'\n> '`" message

Shows:

显示:

Please Enter a Message:
> _

...where _ is where the cursor ends up. Note that since trailing newlines are usually dropped during command substitution, I've included the > afterward. But actually, your original question doesn't seem to want that prompt bit, so:

…其中_是光标最后的位置。注意，由于在命令替换过程中通常会删除尾随的换行，所以我在之后将>包含进来。但实际上，你最初的问题似乎并不想要这样的提示，所以:

# Get a carriage return into `cr` -- there *has* to be a better way to do this
cr=`echo $'\n.'`
cr=${cr%.}

# Use it
read -p "Please Enter a Message: $cr" message

Shows

显示

Please Enter a Message:
_

There has to be a better way, though.

不过，必须有更好的办法。

#2

Just looking for the exact same thing. You can use:

只是寻找完全一样的东西。您可以使用:

# -r and -e options are unrelated to the answer.
read -rep $'Please Enter a Message:\n' message

And it will work exactly as asked:

它的工作原理是这样的:

Please enter a Message:
_

Here is an extract from the bash manpage explaining it:

下面是bash manpage解释它的摘录:

Words of the form $'string' are treated specially. The word expands to string, with backslash-escaped characters replaced as specified by the ANSI C standard. Backslash escape sequences, if present, are decoded as follows:

格式$'string'的单词是专门处理的。单词扩展为字符串，由ANSI C标准指定的反斜线字符替换。反斜杠转义序列，如果存在，被解码如下:

(...)

(…)

\n new line

\ n新行

(...)

(…)

The expanded result is single-quoted, as if the dollar sign had not been present.

扩大的结果是单引号，好像美元符号没有出现。

Took me a while to find out.

花了一段时间才发现。

Note that single quotes and double quotes behave differently in this regard:

注意单引号和双引号在这方面有不同的表现:

A double-quoted string preceded by a dollar sign ($) will cause the string to be translated according to the current locale. If the cur- rent locale is C or POSIX, the dollar sign is ignored. If the string is translated and replaced, the replacement is double-quoted.

一个以美元符号($)开头的双引号字符串将会根据当前的语言环境来翻译字符串。如果当前的地区是C或POSIX，美元符号将被忽略。如果字符串被翻译和替换，则替换为双引号。

#3

$ read -p "Please Enter a Message:
> " message
Please Enter a Message:

Typing a "newline" between ':' and '"' directly.

在“:”和“”之间输入“换行”。

#4

Just to improve the answers of Huang F. Lei and of T.J. Crowder which I like (and added +1) .. You can use one of the following syntaxes too, which basically are the same, it depends on your taste (I prefer the first one):

仅仅是为了改进我喜欢的黄F. Lei和T.J. Crowder的答案(并添加了+1)。你也可以使用以下的一种语法，这基本上是一样的，这取决于你的口味(我更喜欢第一个):

read -p "$(echo -e 'Please Enter a Message: \n\b')" message
read -p "`echo -e 'Please Enter a Message: \n\b'`" message

which both will produce the following output:

两者都将产生以下输出:

Please Enter a Message: 
_

where _ is the cursor.
In case you need a newline in any part of the string but the end, you can use \n, for example

在哪里_是光标。如果您需要在字符串的任何部分中换行，但是最后，您可以使用\n，例如。

read -p "`echo -e '\nPlease Enter\na Message: '`" message

will produce

将会产生

.
Please Enter
a Message: _

where . is a blank first new line and _ is the cursor.

Only to add a final trailing newline you have to use \n\b as in my first example

在哪里。是一个空白的第一个新行和_是游标。在我的第一个例子中，只需要添加最后的拖尾换行，就必须使用\n\b。

#5

From the bash manpage:

从bash从:

-p prompt
   Display prompt on standard error, without a trailing new-
   line, before attempting to read any input.  The prompt is
   displayed only if input is coming from a terminal.

So, not with read itself, and putting \n in the message string just echoes \n. The answer should be simple though - don't get read to display the prompt:

所以，不是通过读取本身，并且在消息字符串中放入\n，只是回传了\n。答案应该是简单的-不要被阅读来显示提示:

echo "Please Enter a Message:" 1>&2
read message

#6

Here's an improvement on the accepted answer that doesn't require spawning a subshell:

这是一个对已接受的答案的改进，它不需要生成一个子shell:

read -p "Please Enter a Message:"$'\n' message

From the GNU Bash reference manual:

从GNU Bash参考手册:

Words of the form $'string' are treated specially. The word expands to string, with backslash-escaped characters replaced as specified by the ANSI C standard.

格式$'string'的单词是专门处理的。单词扩展为字符串，由ANSI C标准指定的反斜线字符替换。

#7

-2

read -p "Please Enter a Message:Return" message

读-p“请输入一条信息:返回”信息。

#1