UNIX for Dummies Questions & Answers

Hello!

My final exam in my Linux class is tomorrow, and I was just reviewing the grep and sed commands. I came across an example, by which I got stumped: it asks to provide a sed command that deletes all lines that contain exactly 3 to 5 digit strings, from a file.
In this case, I created a file that looks like this:

Line 1
Line 22
Line 333
Line 4444
Line 55555
Line 666666

So this sed command should print out only:

Line 1
Line 22
Line 666666

I tried the following command: sed '/[0-9]{3,5}/d' Lines.txt
but it doesn't do anything....

Could anyone please tell me my mistake?
THANK YOU!!

Hi,

You need to match the space also.
Try this

Code:

 sed -r '/\s[0-9]{3,5}$/d' file.txt

Ohhh, I didn't realize I have to match the space too! Now I know!

Thank You so much for helping me out!!