Input file:
$ cat file.txt
1 172.17.4.1
2 172.17.4.5
3 172.17.4.8
4 172.27.4.19
5 172.24.4.12
Now:
$ grep '172.17.4.1' file.txt
1 172.17.4.1
4 172.17.4.19
5 172.17.4.12
Are you trying to grep exact '172.17.4.1' ?
From grep man pages:
-w, --word-regexp
Select only those lines containing matches that form whole words. The test is that the matching substring must either be at the beginning of the line, or preceded by a non-word constituent character. Similarly, it must be either at the end of the line or followed by a non-word constituent character. Word-constituent characters are letters, digits, and the underscore.
$ grep -w '172.17.4.1' file.txt
1 172.17.4.1
Another alternative:
$ grep '\<172.17.4.1\>' file.txt
1 172.17.4.1
Normal awk match:
$ awk '$2 ~ /172.17.4.1/ {print $1}' file.txt
1
4
5
To make it exact match,
From gawk man pages
\y
matches the empty string at either the beginning or the end of a word.
So,
$ awk '$2 ~ /\y172.17.4.1\y/ {print $1}' file.txt
1
For exact match in awk, you can use this though
$ awk '$2=="172.17.4.1" {print $1}' file.txt
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5 comments:
Thanks for the awk $2=='' trick, really handy!!!
Thanks
it works !!
Pfff....searched for an hour on a exact string match with grep command and found it here with grep -w
Thanks a lot man!
@caezsar, thanks !
Be aware that the expression:
grep -w "172.42"
will match 172x42 as also 172.42 since the . means to match any char.
So either we turn off the metacharacters in the grep regexp (172\.42)
or better yet use the -F option, like as
grep -Fw "172.42"
which instructs grep to treat the regexps as fixed strings.
HTH
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