Grep Lines from File with spaces

Question

I have File which contains Records

qwe.google.com IN A 1.1.1.1
qwe.google.com   IN {uneven-space} A{space}1.1.1.1
qwe.google.com  IN     CNAME      asd.google.com

I need to grep all the lines which contains IN A, as it contains uneven spaces in between i am not able to do so.

Can IN A appear anywhere except exactly where you want to match on if? For example could a string containing IN A like TIN APPLES appear in your input? — Ed Morton, Jun 11 '20 at 03:12

binarysta · Accepted Answer · 2020-06-09T13:33:43.303

5

You can use

grep -E "IN[[:blank:]]+A" file

[[:blank:]] matches spaces and tabs, similar to [ \t]

edited Jun 09 '20 at 13:33

answered Jun 09 '20 at 13:28

binarysta

3,032

And assuming GNU grep: grep -P 'IN\s+A' file – glenn jackman Jun 09 '20 at 15:25
Note that [[:blank:]] matches SPC and TAB in the C/POSIX locale, but potentially many more blank characters in others. – Stéphane Chazelas Jun 10 '20 at 08:29

AdminBee · Answer 2 · 2020-06-10T07:52:45.657

2

You can use

grep -E "IN +A" file

which will match (via extended regular expressions) one or more whitespaces between IN and A.

If there can be other forms of whitespace (namely tabs) in between IN and A, you may need to use a character list or character class instead of the simple space, see this answer for example.

edited Jun 10 '20 at 07:52

answered Jun 09 '20 at 13:25

AdminBee

22,803

Tried, but it misses all the rest of "IN A" in result. – user416391 Jun 09 '20 at 13:27
Can you edit your example to include these lines? – AdminBee Jun 09 '20 at 13:29
1

with BRE you can do: 'IN \+A' – pLumo Jun 09 '20 at 13:40
2

@pLumo, only with GNU BRE implementations or compatible. \+ is unspecified in POSIX BRE. In POSIX BRE, it would be \{1,\} instead of \+. – Stéphane Chazelas Jun 10 '20 at 08:31
The GNU trap once again. thanks for pointing me to that. – pLumo Jun 10 '20 at 08:33

score 1 · Answer 3 · answered Jun 10 '20 at 08:27

awk '$2 == "IN" && $3 == "A"'

May be closer to what you want (look for internet A records in that output).

With grep:

grep -E '[[:blank:]]IN[[:blank:]]+A[[:blank:]]'

would be better than just

grep -E 'IN[[:blank:]]+A'

Which could match on a line like:

example.com   IN      TXT     "v=spf1 include:EXAMPLE.IN ALL"

for instance.

In any case, both grep commands would match on:

example.com   IN      TXT     "blah IN A bleh"

Grep Lines from File with spaces

3 Answers3