org.unix4j.unix

Class Tail

java.lang.Object

org.unix4j.unix.Tail

public final class Tail
extends Object

Non-instantiable module with inner types making up the tail command.

NAME

tail - display the last part of a file

SYNOPSIS

	tail
	tail <args>
	tail <count>
	tail [-cqs] <count>
	tail <files>
	tail <count> <files>
	tail <count> <paths>
	tail [-cqs] <count> <files>
	tail [-cqs] <count> <paths>

See Tail.Interface for the corresponding command signature methods.

DESCRIPTION

This filter displays the first count lines or characters of each of the specified files, or of the standard input if no files are specified. If count is omitted it defaults to 10. Both line and character counts start from 1.

If more than a single file is specified, each file is preceded by a header consisting of the string "==> XXX <==" where "XXX" is the name of the file.

Options

The following options are supported:

	-c		--chars		The count argument is in units of characters instead of lines. Starts from 1 and includes line ending characters.
	-q		--suppressHeaders		Suppresses printing of headers when multiple files are being examined.
	-s		--countFromStart		The count argument is relative to the beginning of the file instead of counting from the end of the file. For instance, tail -s 10 prints the lines starting from line 10; tail -s 1 prints the whole file.

OPERANDS

The following operands are supported:

	<count>	:	long		The last count lines of each input file are copied to standard output, starting from 1 (characters instead of lines if the -c option is specified, and offset from start instead of end with -s option). Must be a non-negative integer or an exception is thrown. If count is greater than the number number of lines (characters) in the input, the application will not error and send the whole file to the output.
	<paths>	:	String...		Pathnames of the input files to be filtered; wildcards * and ? are supported; relative paths are resolved on the basis of the current working directory.
	<files>	:	java.io.File...		The input files to be filtered; relative paths are not resolved (use the string paths argument to enable relative path resolving based on the current working directory).
	<args>	:	String...		String arguments defining the options and operands for the command. Options can be specified by acronym (with a leading dash "-") or by long name (with two leading dashes "--"). Operands other than the default "--paths" operand have to be prefixed with the operand name (e.g. "--count" for a subsequent count operand value).
	<options>	:	TailOptions		Options for the tail command.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	Tail.Interface<R> Interface defining all method signatures for the "tail" command.

Field Summary

Fields

Modifier and Type	Field and Description
static TailFactory	Factory Singleton factory instance for the "tail" command.
static String	NAME The "tail" command name.
static TailOptionSets	Options Options for the "tail" command: c, q, s.

Method Summary

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

NAME

public static final String NAME

The "tail" command name.

See Also:

Constant Field Values

Options

public static final TailOptionSets Options

Options for the "tail" command: c, q, s.

	-c		--chars		The count argument is in units of characters instead of lines. Starts from 1 and includes line ending characters.
	-q		--suppressHeaders		Suppresses printing of headers when multiple files are being examined.
	-s		--countFromStart		The count argument is relative to the beginning of the file instead of counting from the end of the file. For instance, tail -s 10 prints the lines starting from line 10; tail -s 1 prints the whole file.

Factory

public static final TailFactory Factory

Singleton factory instance for the "tail" command.