So, you have a large file… now what?  Well, I did say a few things you can do to find specific things, but what if you want lines around the specific stuff you found…

The story thus far, from an SSH terminal window.

cat file.txt | grep something

All fine and dandy.  However, if you want surrounding lines, not so fine and dandy.

Ok, first off there is an n flag for grep that will print line numbers for each found line.  At least we know where to look.

I found on the internet another blog which said I could pull a specific amount of lines from a file by using more and head.  The syntax is something like this.

more +N file | head -n 1

Source is http://notfaq.wordpress.com/

So, we have a way to get the lines we need.  In Cygwin, I make the command I need… and it doesn’t work, “more” isn’t installed.  I cannot find it either.

Another search later, I find out that more is in the util-linux package for Cygwin.   Note that this package installs Perl for the Cygwin environment as well, but oh well.

Source for that information is in this Cygwin Mailing List Post

So, from all of that, what do we have?  We have a way to pull surrounding lines from a search result hit.  This goes somewhat slower than the search, but it is at least something that can be done when you really want those surrounding lines.  Note that you can also tail -n # to get the # of lines at the bottom of a query.  Anyways…

cat file.txt | grep -n search

more +# | head -n #

First # is the line number, second # is the amount of lines you want.  You use head because the more command gives you the “whole file” from that line number to the end of file.

One last thing, there is a split command but I haven’t found a use for it yet.  It appears you can split  files apart and smash them together with cat later on.  Some information is at the link below.

http://en.wikipedia.org/wiki/Split_%28Unix%29

That’s it!