sed 命令无法按预期从文件中删除特定行

Question

I have try to use sed command for delete particular line from file but it seems not working properly in my system (CentOS release 6.3 (Final).

my file1.txt contain following data

line1
line2
line3
line4
line5

Now i try below command to delete 3rd line from the file.

$ sed '3d' file1.txt 

And output of above command is

line1
line2
line4
line5

But when i check original file then it seems nothing deleted. 3rd line is there.

So any one have idea why sed not working?

Answer 1

使其在线 sed：

sed -i.bak '3d' file1.txt

Answer 2

To delete particular lines from a file using sed without creating a backup:

sed -i '' -e '3,6d' file1.txt

The command above will remove lines 3 up to and including 6 from file1.txt , without creating a backup