File:
cat test.txt
100 ***
10 ** // target
Grep:
grep -E '\*{2}' test.txt
100 ***
10 **
Isn't the {m} used to do exact the number of the match?
How to get the * with exact 2 occurrence?
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@WiktorStribiżew, you are too fast. I intended to ask about the special character. the \b does not work. Can you take a look? – newID Jun 16 '19 at 20:17
2 Answers
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You may use
grep -E '(^|[^*])\*{2}($|[^*])' test.txt
See online grep demo:
test="100 ***
10 ** // target"
grep -E '(^|[^*])\*{2}($|[^*])' <<< "$test"
# => 10 ** // target
Details
(^|[^*])- start of string or any char but*\*{2}- two asterisks($|[^*])- end of string or any char but*.
Variation with whitespace boundaries
If you need to only match a "word" in between spaces use
grep -E '(^|[[:space:]])\*{2}($|[[:space:]])' test.txt
Wiktor Stribiżew
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A simple basic regular expression will work as well explicitly specifying "**" not surrounded by a '*'. For example:
$ grep '^[^*]*[*][*][^*]*$' test.txt
10 **
That will match the line containing [*][*] anywhere in the line not surrounded by another '*'.
David C. Rankin
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