Count lines of CLI output in linux

Question

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.

@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
– hek2mgl, Commented Aug 3, 2016 at 15:30

hek2mgl · Accepted Answer · 2016-08-03 15:41:36Z

6

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}'

edited Aug 3, 2016 at 15:41

answered Aug 3, 2016 at 15:28

hek2mgl

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1 Comment

questionto42 Over a year ago

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.

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