DragonFly On-Line Manual Pages

TAIL(1)                DragonFly General Commands Manual               TAIL(1)

NAME
     tail - display the last part of files

SYNOPSIS
     tail [-F | -f | -r] [-q | -v] [-b number | -c number | -n number]
          [file ...]

DESCRIPTION
     The tail utility displays the contents of file or, by default, its
     standard input, to the standard output.

     The display begins at a byte, line or 512-byte block location in the
     input.  Numbers having a leading plus ("+") sign are relative to the
     beginning of the input, for example, "-c +2" starts the display at the
     second byte of the input.  Numbers having a leading minus ("-") sign or
     no explicit sign are relative to the end of the input, for example, "-n
     2" displays the last two lines of the input.  The default starting
     location is "-n 10", or the last 10 lines of the input.

     The options are as follows:

     -b number
             The location is number 512-byte blocks.

     -c number
             The location is number bytes.

     -f      The -f option causes tail to not stop when end of file is
             reached, but rather to wait for additional data to be appended to
             the input.  The -f option is ignored if the standard input is a
             pipe, but not if it is a FIFO.

     -F      The -F option implies the -f option, but tail will also check to
             see if the file being followed has been renamed or rotated.  The
             file is closed and reopened when tail detects that the filename
             being read from has a new inode number.  The -F option is ignored
             if reading from standard input rather than a file.

     -n number
             The location is number lines.

     -q      Suppresses printing of headers when multiple files are being
             examined.

     -r      The -r option causes the input to be displayed in reverse order,
             by line.  Additionally, this option changes the meaning of the
             -b, -c and -n options.  When the -r option is specified, these
             options specify the number of bytes, lines or 512-byte blocks to
             display, instead of the bytes, lines or blocks from the beginning
             or end of the input from which to begin the display.  The default
             for the -r option is to display all of the input.

     -v      Always prints a header for each file, even if only a single file
             is specified.

     If more than a single file is specified, or the -v flag is used, each
     file is preceded by a header consisting of the string "==> XXX <==" where
     "XXX" is the name of the file.  The -q flag disables the printing of the
     header in both cases.

EXIT STATUS
     The tail utility exits 0 on success, and >0 if an error occurs.

SEE ALSO
     cat(1), head(1), sed(1), tac(1)

STANDARDS
     The tail utility is expected to be a superset of the IEEE Std 1003.2-1992
     ("POSIX.2") specification.  In particular, the -F, -b and -r options are
     extensions to that standard.

     The historic command line syntax of tail is supported by this
     implementation.  The only difference between this implementation and
     historic versions of tail, once the command line syntax translation has
     been done, is that the -b, -c and -n options modify the -r option, i.e.
     "-r -c 4" displays the last 4 characters of the last line of the input,
     while the historic tail (using the historic syntax "-4cr") would ignore
     the -c option and display the last 4 lines of the input.

HISTORY
     A tail command appeared in PWB UNIX.

DragonFly 5.9-DEVELOPMENT        June 20, 2020       DragonFly 5.9-DEVELOPMENT