Subject: bug#39951: tail -n +NUM is not working properly

From: Bernhard Voelker <[email-masked]>
Date: Fri, 6 Mar 2020 18:35:24 +0100

On 3/6/20 10:42 AM, Dimitris Moraitidis wrote:
> Hey there,
> 
> tail -n + NUM does not return the desired output. +NUM starts from the top
> of the file, not from the bottom.
> 
> So for example, given the following file:
> 
>> this
>> is
>> an
>> example
>> file
>> each
>> word
>> represents
>> a
>> line
> 
> and executing tail -n +3 example, I am getting
> 
>> example
>> file
>> each
>> word
>> represents
>> a
>> line
> 
> instead of
> 
> 
>> this
>> is
>> an
>> example
>> file
>> each
>> word
> 
> I am using *tail (GNU coreutils) 8.28 *in latest ubuntu 18.04 LTS
> 
> Thanks in advance for looking into this :)

Isn't this exactly what tail(1) is support to do when the user explicitly
passes the '+' sign to the number?

   $ tail --help | grep -A1 -- --lines
     -n, --lines=[+]NUM       output the last NUM lines, instead of the last 10;
                                or use -n +NUM to output starting with line NUM

Also POSIX says so:
https://pubs.opengroup.org/onlinepubs/9699919799/utilities/tail.html

Have a nice day,
Berny