Hi have the following command:
lsscsi | grep HITACHI | awk '{print $6}'
I want that the output will be the number of lines of the original output. For example, if the original output is:
/dev/sda
/dev/sdb
/dev/sdc
The final output will be 3.
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Omri
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3`lsscsi | grep HITACHI | awk '{print $6}' | wc -l` – Juan Tomas Aug 03 '16 at 15:17
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Thanks. So easy :) – Omri Aug 03 '16 at 15:18
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1@JuanTomas Never use `grep foo | awk '{print $1}'`. It should be `awk '/foo/{print $1}'`. If you use `awk`, `grep` is not required meaning unnecessary overhead. – hek2mgl Aug 03 '16 at 15:30
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Possible duplicate of [How to count lines in a document?](http://stackoverflow.com/questions/3137094/how-to-count-lines-in-a-document) – hek2mgl Aug 03 '16 at 15:33
1 Answers
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Basically the command wc -l can be used to count the lines in a file or pipe. However, since you want to count the number of lines after a filter has been applied I would recommend to use grep for that:
lsscsi | grep -c 'HITACHI'
-c just prints the number of matching lines.
Another thing. In your example you are using grep .. | awk. That's a useless use of grep. It should be
lsscsi | awk '/HITACHI/{print $6}'
hek2mgl
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What is meant here is that `lsscsi | grep -c 'HITACHI'` and `lsscsi | grep 'HITACHI'|wc -l` will have the same console output: just the number of lines. – questionto42 Jan 16 '23 at 01:53