What does the + symbol mean in the following grep regular expression:
grep ‘^d[aei]\+d$’ /usr/share/dict/words
A.
Match the preceding character set ([aei]) one or more times.
B.
Match the preceding character set ([aei]) zero or more times.
C.
Match the preceding character set ([aei]) zero or one times.
D.
Match a literal + symbol.
Explanation:
The answer should be “Match a literal + symbol” because there is a backslash symbol before the
plus, so it should match a literal +.
The correct answer is A.
echo -n “daeiiiiad” | grep –color “^d[aei]\+d$”
daeiiiiad
echo -n “da+d” | grep –color “^d[aei]\+d$”
root:/home/muza $ echo -n “da+d” | grep –color “^d[aei]+d$”
da+d
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Yes it’s “A”
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In basic regular expressions the meta-characters ?, +, {, |, (, and ) lose their special meaning; instead use the backslashed versions \?, \+, \{, \|, \(, and \).
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