Delete lines that contain two dots, with characters between the dots

Question

How would I delete all lines (from a text file) which contain only two dots, with random data between the dots. Some lines have three or more dots, and I need those to remain in the file. I would like to use sed.

Example Dirty File:

.dirty.dig
.please.dont.delete.me
.delete.me
.dont.delete.me.ether
.nnoooo.not.meee
.needto.delete

Desired Output:

.please.dont.delete.me
.dont.delete.me.ether
.nnoooo.not.meee

score 2 · Answer 1 · answered Apr 15 '17 at 07:34

2

Would be simpler to use awk here

$ awk -F. 'NF!=3' ip.txt
.please.dont.delete.me
.dont.delete.me.ether
.nnoooo.not.meee

-F. use . as delimiter
NF!=3 print all lines where number of input fields is not equal to 3
- this will retain lines like abc.xyz
- to retain only lines with more than 2 dots, use awk -F. 'NF>3' ip.txt

answered Apr 15 '17 at 07:34

Sundeep

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I apologize, my data had some hyphens at the ends of the lines which were interfearing, this actually works incredibly well. – derpderpalert Apr 16 '17 at 01:11

score 1 · Answer 2 · edited May 23 '17 at 12:25

1

sed '/^[^.]*\.[^.]*\.[^.]*$/d' file

Output:

.please.dont.delete.me
.dont.delete.me.ether
.nnoooo.not.meee

See: The Stack Overflow Regular Expressions FAQ

edited May 23 '17 at 12:25

Community

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1

answered Apr 15 '17 at 07:28

Cyrus

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Ed Morton · Answer 3 · 2017-04-15T18:33:15.047

1

sed is for making substitutions, to just Globally search for a Regular Expression and Print the result there's a whole other tool designed just for that purpose and even named after it - grep.

grep -v '^[^.]*\.[^.]*\.[^.]*$' file

or with GNU grep for EREs:

$ grep -Ev '^[^.]*(\.[^.]*){2}$' file
.please.dont.delete.me
.dont.delete.me.ether
.nnoooo.not.meee

edited Apr 15 '17 at 18:33

answered Apr 15 '17 at 18:19

Ed Morton

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I apologize, my data had some hyphens at the ends of the lines which were interfearing, this actually works incredibly well. – derpderpalert Apr 16 '17 at 01:12

score 0 · Answer 4 · answered Apr 15 '17 at 07:29

0

I don't have a sed handy to double-check, but

/^[^.]*\.[^.]*\.[^.]*$/d

should match and delete all lines that have two dots with non-dot strings before and between them.

answered Apr 15 '17 at 07:29

Ulrich Schwarz

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score 0 · Answer 5 · answered Apr 15 '17 at 11:43

0

This might work for you (GNU sed):

sed 's/\./&/3;t;s//&/2;T;d' file

If there are 3 or more . print. If there are 2 . delete. Otherwise print.

Another way:

sed -r '/^([^.]*\.[^.]*){2}$/d' file

answered Apr 15 '17 at 11:43

potong

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`-r` will only work in GNU sed while `-E` will work in both GNU and OSX seds so using `-E` would be more portable than using `-r`. – Ed Morton Apr 15 '17 at 18:35
Works great when I run that by hand, but from a bash script, it wont work. – derpderpalert Apr 16 '17 at 00:34
I apologize, my data had some hyphens at the ends of the lines which were interfearing, this actually works incredibly well. – derpderpalert Apr 16 '17 at 01:12

Delete lines that contain two dots, with characters between the dots

5 Answers5