[RndTbl] Easy script question?
Gilbert E. Detillieux
gedetil at cs.umanitoba.ca
Wed Mar 4 16:19:07 CST 2015
Sometimes, it's the simple solutions that elude us... :)
But wait! Compatibility alert! Using a negative line count on head(1)
is a GNU extension, and likely won't work with more "traditional" UNIX
implementations.
Gilbert
On 04/03/2015 4:10 PM, John Lange wrote:
> 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
> <mailto: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 <mailto: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
--
Gilbert E. Detillieux E-mail: <gedetil at muug.mb.ca>
Manitoba UNIX User Group Web: http://www.muug.mb.ca/
PO Box 130 St-Boniface Phone: (204)474-8161
Winnipeg MB CANADA R2H 3B4 Fax: (204)474-7609
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