What does the following command do? grep -vn "abc" x
2015
What does the following command do?
grep -vn "abc" x
- A.
It will print all of the lines in the file x that match the search string "abc"
- B.
It will print all of the lines in file x that do not match the search string "abc"
- C.
It will print the total number of lines in the file x that match the search string "abc"
- D.
It will print the specific line numbers of the file x in which there is a match for string "abc"
Attempted by 40 students.
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Correct answer: B
Answer: The command prints all lines in file x that do NOT contain the string "abc", and each printed line is prefixed with its line number.
-v : invert match — select lines that do not match the pattern.
-n : show line numbers before each output line.
Combined effect: grep -vn "abc" x outputs every line that does not contain "abc", with each output line prefixed by its line number.
Example: If file x has three lines where line 1 is "apple", line 2 is "abc", and line 3 is "banana", then grep -vn "abc" x will print:
1:apple
3:banana