How to handle "-" in grep?

Question

Its been asked several times but its not clear to me yet.

I have the following text in a file ( data.txt, tab delimeted ):

ABC 12 ABC-AS 14 DEF 18 DEF-AS 9

Now I want to search for ABC and DEF, but not ABC-AS, DEF-AS as a result.

grep -w ABC data.txt

Output:

grep -w ABC data.txt ABC ABC-AS grep --no-group-separator -w "ABC" data.txt ABC ABC-AS grep --group-separator="\t" -w "ABC" data.txt ABC ABC-AS

If your version of grep has Perl regexes available, you can use a negative lookahead. You can look for ABC and then post-filter grep -v 'ABC-[A-Z]' or thereabouts. — Jonathan Leffler
– Jonathan Leffler, Commented Sep 28, 2017 at 15:59
With the revised description, can you use grep '^ABC[[:space:]]' to find the lines that start with ABC and not ABC-AS? Or grep -E '^(ABC|DEF)[[:space:]]' if you want DEF too. — Jonathan Leffler
– Jonathan Leffler, Commented Sep 28, 2017 at 16:06
Or grep "ABC\s" data.txt. For multiple patterns: grep -e "ABC\s" -e "DEF\s" data.txt — Intelligent Shade of Blue
– Intelligent Shade of Blue, Commented Sep 28, 2017 at 16:11

Benoît Zu · Accepted Answer · 2017-09-29 08:06:04Z

With a regex

grep -E "(ABC|DEF)[^\-]" data.txt

Details

(ABC|DEF): Match "ABC" or "DEF"

[^\-]: Anything except "-"

Output

ABC 12 DEF 18

MyCuky LoVe · Accepted Answer · 2017-09-28 15:58:57Z

1

Try this, which select only those matches that exactly match the whole line

grep --line-regexp "ABC" data.txt

answered Sep 28, 2017 at 15:58

768 bronze badges

2 Comments

I am sorry. the file contains other columns. I updated the query to reflect exact situation.

In this case, try this: grep "ABC[[:blank:]]" .\data.txt