NAME
tail – deliver the last part of a file
SYNOPSIS
/usr/bin/tail [ + _s number [lbcr]] [file]
/usr/bin/tail [-lbcr] [file]
/usr/bin/tail [ + _ number [lbcf]] [file]
/usr/bin/tail [-lbcf] [file]
/usr/xpg4/bin/tail [-f | -r] [-c number | -n number]
[file]
/usr/xpg4/bin/tail [ + _ number [l | b | c] [f]] [file]
/usr/xpg4/bin/tail [ + _ number [l] [f | r] ] [file]
DESCRIPTION
The tail utility copies the named file to the standard out-
put beginning at a designated place. If no file is named,
the standard input is used.
Copying begins at a point in the file indicated by the
-cnumber, -nnumber, or + _number options (if +number is speci-
fied, begins at distance number from the beginning; if
-number is specified, from the end of the input; if number
is NULL, the value 10 is assumed). number is counted in
units of lines or byte according to the -c or -n options,
or lines, blocks, or bytes, according to the appended option
l, b, or c. When no units are specified, counting is by
lines.
OPTIONS
The following options are supported for both /usr/bin/tail
and /usr/xpg4/bin/tail. The -r and -f options are mutually
exclusive. If both are specified on the command line, the -f
option is ignored.
-b Units of blocks.
-c Units of bytes.
-f Follow. If the input-file is not a pipe, the pro-
gram does not terminate after the line of the
input-file has been copied, but enters an endless
loop, wherein it sleeps for a second and then
attempts to read and copy further records from the
input-file. Thus it can be used to monitor the
growth of a file that is being written by some
other process.
-l Units of lines.
-r Reverse. Copies lines from the specified starting
point in the file in reverse order. The default for
r is to print the entire file in reverse order.
/usr/xpg4/bin/tail
The following options are supported for /usr/xpg4/bin/tail
only:
-c number The number option-argument must be a decimal
integer whose sign affects the location in
the file, measured in bytes, to begin the
copying:
+ Copying starts relative to the
beginning of the file.
– Copying starts relative to the end
of the file.
none Copying starts relative to the end
of the file.
The origin for counting is 1; that is, -c+1
represents the first byte of the file, -c-1
the last.
-n number Equivalent to -cnumber, except the starting
location in the file is measured in lines
instead of bytes. The origin for counting is
1. That is, -n+1 represents the first line
of the file, -n-1 the last.
OPERANDS
The following operand is supported:
file A path name of an input file. If no file operands
are specified, the standard input is used.
USAGE
See largefile(5) for the description of the behavior of tail
when encountering files greater than or equal to 2 Gbyte ( 2
**31 bytes).
EXAMPLES
Example 1: Using the tail Command
The following command prints the last ten lines of the file
fred, followed by any lines that are appended to fred
between the time tail is initiated and killed.
example% tail -f fred
The next command prints the last 15 bytes of the file fred,
followed by any lines that are appended to fred between the
time tail is initiated and killed:
example% tail -15cf fred
ENVIRONMENT VARIABLES
See environ(5) for descriptions of the following environment
variables that affect the execution of tail: LANG, LC_ALL,
LC_CTYPE, LC_MESSAGES, and NLSPATH.
EXIT STATUS
The following exit values are returned:
0 Successful completion.
>0 An error occurred.
ATTRIBUTES
See attributes(5) for descriptions of the following attri-
butes:
/usr/bin/tail
User Commands tail(1)
____________________________________________________________
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
|_____________________________|_____________________________|
| Availability | SUNWcsu |
|_____________________________|_____________________________|
| CSI | Enabled |
|_____________________________|_____________________________|
/usr/xpg4/bin/tail
____________________________________________________________
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
|_____________________________|_____________________________|
| Availability | SUNWxcu4 |
|_____________________________|_____________________________|
| CSI | Enabled |
|_____________________________|_____________________________|
| Interface Stability | Standard |
|_____________________________|_____________________________|
SEE ALSO
cat(1), head(1), more(1), pg(1), dd(1M), attributes(5),
environ(5), largefile(5), standards(5)
NOTES
Piped tails relative to the end of the file are stored in a
buffer, and thus are limited in length. Various kinds of
anomalous behavior can happen with character special files.