bash sed 用字符替换空行
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sed replace empty line with character
提问by cebach561
How do you replace a blank line in a file with a certain character using sed?
如何使用 sed 用某个字符替换文件中的空行？
I have used the following command but it still returns the original input:
我使用了以下命令，但它仍然返回原始输入：
sed 's/^$/>/' filename
Original input:
原始输入：
ACTCTATCATC
CTACTATCTATCC
CCATCATCTACTC
...
Desired output:
期望的输出：
ACTCTATCATC
>
CTACTATCTATCC
>
CCATCATCTACTC
>
...
Thanks for any help
谢谢你的帮助
回答by jaypal singh
Here is a way with awk. This wouldn't care if you have spaces or blank lines:
这是awk. 如果您有空格或空行，这不会在乎：
awk '!NF{$ cat -vet file
ACTCTATCATC$
$
CTACTATCTATCC$
$
CCATCATCTACTC$
$
=">"}1' file
NFstands for number of fields. Since blank lines or lines with just spaces have no fields, we use that to insert your text. 1triggers the condition to be trueand prints the line:
NF代表字段数。由于空行或只有空格的行没有字段，我们使用它来插入您的文本。1触发条件为true并打印该行：
Test:
测试：
$ awk '!NF{sed 's/^\s*$/>/' filename
=">"}1' file
ACTCTATCATC
>
CTACTATCTATCC
>
CCATCATCTACTC
>
$are end of line markers
$是行尾标记
sed 's/^[[:blank:]]*$/>/' filename
回答by Firas Moalla
You may have tabs or white spaces in your filename' empty lines, try the following:
filename' 空行中可能有制表符或空格，请尝试以下操作：
sed -i 's/^[[:space:]]*$/string/' foo
回答by Raman Shah
You may have whitespace in your input. First thing to try is:
您的输入中可能有空格。首先要尝试的是：
sed 's/^$/\>/g' filename
回答by sridharn
The following code should work:
以下代码应该可以工作：
sed '/^$/d' filename
回答by kisHoR
What's missing here is the escape character. This will work for you.
这里缺少的是转义字符。这对你有用。
##代码##And if you need to delete the empty lines and print others, Try
如果您需要删除空行并打印其他行，请尝试
##代码##