[RndTbl] Easy script question?

John Lange john at johnlange.ca
Wed Mar 4 16:10:25 CST 2015


man head

head --lines=-5 textfile.txt

all but the last 5 lines.


On Wed, Mar 4, 2015 at 3:49 PM, Robert Keizer <robert at keizer.ca> wrote:

> Idea from thread below:
>
> | awk '{if(a) print a;a=b;b=$0}'
>
> Note that you might want to include a little more logic if you want
> blanklines in there..  This doesn't store all of it in a file or in ram.
>
>
>
> http://askubuntu.com/questions/475694/awk-command-to-print-all-the-lines-except-the-last-three-lines
>
> On 2015-03-04 3:33 PM, Adam Thompson wrote:
> > Like Tim said, you first have to know how many lines exist in the file
> > before you can do anything other than stream processing.
> > On moderately-sized inputs, "wc -l" works reasonably well. On large
> > inputs, there's no way to do this efficiently unless you're willing to
> > sacrifice accuracy.
> >
> > F=filename
> > L=$(wc -l $F)
> > head -n $(( $L - num_of_ignored_lines ))
> >
> > -Adam
> >
> > On March 4, 2015 2:36:24 PM CST, Kevin McGregor
> > <kevin.a.mcgregor at gmail.com> wrote:
> >
> >     Can someone help me out? I'm too tired to think straight.
> >
> >     Is there an easy/short way to get all BUT the last n lines of a
> >     text file/input? All I can think of is reversing the input line
> >     order and tail +n or something like that. FYI the input is not
> >     very big.
> >
> >     Kevin
> >
> >
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-- 
John Lange
www.johnlange.ca
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