tail - output trailing portion of one or more files

tail copies one or more input files to standard output starting at a designated point for each file. Copying starts at the point indicated by the options and is unlimited in size.

By default a header of the form ==> filename <== is output before all but the first file but this can be changed with the -q and -v options.

If no file is given, or if the file is -, tail copies from standard input. The start of the file is defined as the current offset.

The option argument for -c can optionally be followed by one of the following characters to specify a different unit other than a single byte:

b

512 bytes.

k

1 KiB.

m

1 MiB.

g

1 GiB.

For backwards compatibility, -number is equivalent to -n number and +number is equivalent to -n -number. number may also have these option suffixes: b c f g k l m r.

-n, --lines=lines

Copy lines lines from each file. A negative value for lines indicates an offset from the end of the file. The default value is 10.

-b, --blocks

Copy units of 512 bytes.

-c, --bytes[=chars]

Copy chars bytes from each file. A negative value for chars indicates an offset from the end of the file. The option value may be omitted.

-f, --forever|follow

Loop forever trying to read more characters as the end of each file to copy new data. Ignored if reading from a pipe or fifo.

-h, --headers

Output filename headers. On by default; -h means --noheaders.

-l, --lines

Copy units of lines. This is the default.

-L, --log

When a --forever file times out via --timeout, verify that the curent file has not been renamed and replaced by another file of the same name (a common log file practice) before giving up on the file.

-q, --quiet

Don't output filename headers. For GNU compatibility.

-r, --reverse

Output lines in reverse order.

-s, --silent

Don't warn about timeout expiration and log file changes.

-t, --timeout=timeout

Stop checking after timeout elapses with no additional --forever output. A separate elapsed time is maintained for each file operand. There is no timeout by default. The default timeout unit is seconds. timeout may be a catenation of 1 or more integers, each followed by a 1 character suffix. The suffix may be omitted from the last integer, in which case it is interpreted as seconds. The supported suffixes are:

s

seconds

m

minutes

h

hours

d

days

w

weeks

M

months

y

years

S

scores

-v, --verbose

Always ouput filename headers.

0

All files copied successfully.

>0

One or more files did not copy.

cat(1), head(1), rev(1)

version

tail (AT&T Research) 2012-06-19

author

Glenn Fowler <gsf@research.att.com>

author

David Korn <dgk@research.att.com>

copyright

Copyright © 1992-2012 AT&T Intellectual Property

license

http://www.eclipse.org/org/documents/epl-v10.html