BASH - 从文本文件中读取多行
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BASH - Reading Multiple Lines from Text File
提问by John Marston
i am trying to read a text file, say file.txt and it contains multiple lines.
我正在尝试读取一个文本文件，比如 file.txt，它包含多行。
say the output of file.txtis
说输出file.txt是
$ cat file.txt
this is line 1
this is line 2
this is line 3
I want to store the entire output as a variable say, $text.
When the variable $textis echoed, the expected output is:
我想将整个输出存储为一个变量，比如$text.
当变量$text被回显时，预期的输出是：
this is line 1 this is line 2 this is line 3
my code is as follows
我的代码如下
while read line
do
test="${LINE}"
done < file.txt
echo $test
the output i get is always only the last line. Is there a way to concatenate the multiple lines in file.txt as one long string?
我得到的输出总是只有最后一行。有没有办法将 file.txt 中的多行连接为一个长字符串？
回答by kev
You can translate the \n(newline) to (space):
您可以将\n（换行符）转换为（空格）：
$ text=$(tr '\n' ' ' <file.txt)
$ echo $text
this is line 1 this is line 2 this is line 3
If lines ends with \r\n, you can do this:
如果行以 结尾\r\n，您可以这样做：
$ text=$(tr -d '\r' <file.txt | tr '\n' ' ')
回答by Fritz G. Mehner
Another one:
另一个：
line=$(< file.txt)
line=${line//$'\n'/ }
回答by Karthi Kulandaivelu
test=$(cat file.txt | xargs)
echo $test
回答by bmk
You have to append the content of the next line to your variable:
您必须将下一行的内容附加到您的变量中：
while read line
do
test="${test} ${LINE}"
done < file.txt
echo $test
Resp. even simpler you could simply read the full file at once into the variable:
分别 更简单的是，您可以简单地一次将完整文件读入变量：
test=$(cat file.txt)
resp.
分别
test=$(tr "\n" " " < file.txt)
If you would want to keep the newlines it would be as simple as:
如果您想保留换行符，它将非常简单：
test=<file.txt
回答by yazu
I believe it's the simplest method:
我相信这是最简单的方法：
text=$(echo $(cat FILE))
But it doesn't preserve multiple spaces/tabs between words.
但它不会在单词之间保留多个空格/制表符。
回答by Fredrik Pihl
Use arrays
使用数组
#!/bin/bash
while read line
do
a=( "${a[@]}" "$line" )
done < file.txt
echo -n "${a[@]}"
output:
输出：
this is line 1 this is line 2 this is line 3
See e.g. tldp section on arrays
参见例如关于数组的 tldp 部分
