tail - deliver the last part of a file

       Tails relative to the end of the file are treasured up in a buffer, and thus are limited in length.

       According to custom, option +number counts lines from 1, and counts blocks and bytes from 0.

       Tail is ignorant of UTF.

                                                                                                    TAIL(1plan9)

Tail  copies the named file to the standard output beginning at a designated place.  If no file is named,
       the standard input is copied.

       Copying begins at position +number measured from the beginning, or -number from the  end  of  the  input.
       Number  is  counted  in lines, 1K blocks or bytes, according to the appended flag or Default is -10l (ten
       ell).

       The further flag causes tail to print lines from the end of the file in reverse  order;  (follow)  causes
       tail, after printing to the end, to keep watch and print further data as it appears.

       The second syntax is that promulgated by POSIX, where the numbers rather than the options are signed.

tailfile
              Print the last 10 lines of a file.

       tail+0ffile
              Print a file, and continue to watch data accumulate as it grows.

       sed10qfile
              Print the first 10 lines of a file.

       tail - deliver the last part of a file

/src/cmd/tail.c

tail [ +-number[lbc][rf] ] [ file ]

       tail [ -fr ] [ -nnlines ] [ -cnbytes ] [ file ]