How to match exact word and string using grep

tomboi · January 11, 2021, 6:19pm

Here is my data file

foo 3535 ab 3355
bar 55523 gdg 6646
foo1 333 xzzz 555
foobar 555 zztt 56
FOO 333 44 66 7
foo 5555 tttt 7777

I type

grep foo input.txt

I get

foo 3535 ab 3355
foo1 333 xzzz 555
foobar 555 zztt 56
foo 5555 tttt 7777

however, i only want:

foo 3535 ab 3355
foo 5555 tttt 7777

Is it possible? How do I tell that to grep? How can I match exact word and string using grep?

monk · January 11, 2021, 10:23pm

How about?

grep "\<foo\>" your_file_name

The \<word\> matches exact words. If you want to match FOO line too, pass the -i option:

grep -i "\<foo\>" your_file_name

nixcraft · January 11, 2021, 6:36pm

Simple:

grep -w "word" filename
grep -i -w "word" filename
grep -i -w "string" filename
# matching multiple words or strings with egrep
grep -E -i -w "word1|word2|word3" input 
egrep -i -w "str1|str2" my.txt

grep options are as follows for matching exact words/strings:

-w : match only whole words
-i : Ignore case distinctions in patterns i.e. all cases matched. For instance, foo, FOO, Foo, FoO and so on.
-E : Extended regular expressions

See our help pages:

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