Use grep to report back only line numbers

I have a file that possibly contains bad formatting (in this case, the occurrence of the pattern \\backslash). I would like to use grep to return only the line numbers where this occurs (as in, the match was here, go to line # x and fix it).

However, there doesn't seem to be a way to print the line number (grep -n) and not the match or line itself.

我可以使用另一个正则表达式来提取行号，但我想确保grep本身不能执行此操作。我认为grep -no最接近，但仍然显示匹配。

grep

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最佳答案

try:

grep -n "text to find" file.ext | cut -f1 -d:

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If you're open to using AWK:

awk '/textstring/ {print FNR}' textfile

In this case, FNR is the line number. AWK is a great tool when you're looking at grep|cut, or any time you're looking to take grep output and manipulate it.

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You're going to want the second field after the colon, not the first.

grep -n "text to find" file.txt | cut -f2 -d:

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All of these answers require grep to generate the entire matching lines, then pipe it to another program. If your lines are very long, it might be more efficient to use just sed to output the line numbers:

sed -n '/pattern/=' filename

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Bash version

    lineno=$(grep -n "pattern" filename)
lineno=${lineno%%:*}

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To count the number of lines matched the pattern:

grep -n "Pattern" in_file.ext | wc -l

To extract matched pattern

sed -n '/pattern/p' file.est

To display line numbers on which pattern was matched

grep -n "pattern" file.ext | cut -f1 -d:

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I recommend the answers with sed and awk for just getting the line number, rather than using grep to get the entire matching line and then removing that from the output with cut or another tool. For completeness, you can also use Perl:

perl -nE 'say $. if /pattern/' filename

or Ruby:

ruby -ne 'puts $. if /pattern/' filename

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using only grep:

grep -n "text to find" file.ext | grep -Po '^[^:]+'