TAIL(1) BSD Reference Manual TAIL(1)
tail - display the last part of a file
tail [-f | -r] [-b number | -c number | -n number] [file ...]
The tail utility displays the contents of file or, by default, its stan-
dard input, to the standard output.
The display begins at a byte, line or 512-byte block location in the in-
put. Numbers having a leading plus (``+'') sign are relative to the be-
ginning 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 loca-
tion is ``-n 10'', or the last 10 lines of the input.
The options are as follows:
The location is number 512-byte blocks.
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.
The location is number lines.
-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.
If more than a single file is specified, each file is preceded by a head-
er consisting of the string ``==> XXX <=='' where ``XXX'' is the name of
The tail utility exits 0 on success, and >0 if an error occurs.
cat(1), head(1), sed(1)
The tail utility is expected to be a superset of the POSIX 1003.2 speci-
fication. In particular, the -b and -r options are extensions to that
The historic command line syntax of tail is supported by this implementa-
tion. The only difference between this implementation and historic ver-
sions 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.
A tail command appeared in Version 7 AT&T UNIX.
4th Berkeley Distribution June 6, 1993 2