Hi,

How to remove the last 10 lines from stdin ?

Thanks 

bob123 wrote:

> How to remove the last 10 lines from stdin ?

For example:

awk 'NR>10{print a[NR%10]}{a[NR%10]=$0}'

you can adapt it to work for a variable number of lines by doing this:

awk -v n=10 'NR>n{print a[NR%n]}{a[NR%n]=$0}'

Using sed:

sed -n ':a;1,10!{P;N;D;};N;ba'

On December 21, 2009 15:51, in comp.unix.shell, bob123@gmail.com wrote:

> Hi,
> 
> How to remove the last 10 lines from stdin ?

head --lines=-10 -


-- 
Lew Pitcher
Master Codewright & JOAT-in-training   | Registered Linux User #112576
Me: http://pitcher.digitalfreehold.ca/ | Just Linux: http://justlinux.ca/
----------      Slackware - Because I know what I'm doing.         ------

2009-12-21, 20:59(+00), pk:
[...]
> Using sed:
>
> sed -n ':a;1,10!{P;N;D;};N;ba'


sed -ne :a -e '1,10!{P;N;D;}' -e 'N;ba'

Bearing in mind that some sed implementations have a limited
pattern space size (though POSIX requires it to be at least 8
kB)

-- 
St�phane

Lew Pitcher wrote:
> On December 21, 2009 15:51, in comp.unix.shell, bob123@gmail.com wrote:
> 
>> Hi,
>>
>> How to remove the last 10 lines from stdin ?
> 
> head --lines=-10 -
> 
> 

$ head --lines=-10 -
head: -10: invalid number of lines

Non-standard, I assume. And not available in older GNU head versions.

Janis

On Dec 22, 4:51=A0am, "bob123" <bob...@gmail.com> wrote:
> Hi,
>
> How to remove the last 10 lines from stdin ?
>
> Thanks

head -n $(( $(wc -l <file) - 10 )) file

> head -n $(( $(wc -l <file) - 10 )) file

nice...