删除最后一个空行
我的 .csv 文件末尾有一个分段符。我尝试使用以下命令删除文件末尾的空行。
sed -i '/^$/d' combined.csv
但它不起作用并且空白行仍然存在。我可以使用以下命令删除最后一行。
sed -i '$d' combined.csv
但是在删除最后一行之前是否可以检查它是否真的为空？
更新：
我使用以下命令来检查每行是否以数字开头。
sed -i '1s/^[^0-9]*//' combined.csv
这仅检查第一行，而不检查其余行。如何让它检查文件中的所有行？这可能会解决我的问题。
There is a para break at the end of my .csv file. I tried to remove the blank line that is at the end of the file using the following command.
sed -i '/^$/d' combined.csv
But it does not work and a blank line is still there. I can remove the last line using the following command.
sed -i '$d' combined.csv
But is it possible to check if the last line is really empty before removing it?
Update:
I am using the following command to check if each line start with a number.
sed -i '1s/^[^0-9]*//' combined.csv
This checks only for the first line and not the rest of the lines. How do I make it check all the lines in the file? This might solve my problem.
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尝试
${/^$/d;}如果它是文件的最后一行，它只会匹配空行。更新：对于第二个问题，只需删除 s 之前的 1，即： sed -i 's/^[^0-9]*//'combined.csv
Try
${/^$/d;}this will only match an empty line if it is the last line of the file.Update: for your second question, just remove the 1 before the s, i.e.:
sed -i 's/^[^0-9]*//' combined.csv很久以前在某个地方发现了这个并保存了该片段。不要问我它是如何工作的：
Found this ages ago somewhere and saved the snippet. Do not ask me how it works:
我用 sed (GNU sed) 4.2.2 尝试过，并删除了所有空行，而不仅仅是空行（如果它是文件的最后一行）。
我发现以下命令对我自己有效，可以完成这项工作。
该命令来自有用的 SED-Oneliner 集合：
http://sed.sourceforge.net/sed1line.txt
I tried it with sed (GNU sed) 4.2.2 and got all blank lines deleted not only the empty line if it is the last line of the file.
I found the following Command, that worked for myself that does the Job.
This Command is from a Collection of useful SED-Oneliners:
http://sed.sourceforge.net/sed1line.txt
要删除空行，您可以使用
grep .或sed '/^$/d'它将删除文件中的任何空行。我希望您的文件中间没有任何空行，但这适用于您的情况。
cat 组合.csv | grep .或
cat合并.csv | sed '/^$/d'To remove blank lines you can use
grep .orsed '/^$/d'It will remove any blank line in the file. I hope you file does not have any blank lines in the middle but this will work in your case.
cat combined.csv | grep .or
cat combined.csv | sed '/^$/d'如果您确定最后一行是空，那么只需使用：
...|头 -n -1 | ...If you know for sure that last line is empty, then just use:
...| head -n -1 | ...