Hey guys,

Something is puzzling me!

I saw someone use the grep in the following way and I'm not sure I understand what it does, and if there's any benefit to using it this way.

I checked the man file which confirmed that -v is relating to matching non grouping lines (which I'm not sure I fully understand either!) but I don't see any difference in the output of the above command versus the same command without the | grep -v query bit..

Why would you pipe grep into grep unless you were searching for something specific within the search results?

Does query mean something else?

grep -v says to exclude the item (i.e. does the opposite of what grep normally does). In this case the user was trying to get output that excluded the word "query".

The most common time you'll see "grep -v" is "grep -v grep" when looking at processes with the ps command.
e.g. ps -ef |grep myprocess |grep -v grep
The reason for this is the line "grep myprocess" is itself a process that the grep would find more often than not and you don't want that - you just want the lines that have myprocess.

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Give me X.X.X.X that don't contain "query".
The implication is that "query" is in other lines as well.

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a practical example:

Awesome, that explains it perfectly!!

Thanks for your help, I've got it, and yes... very handy