org.unix4j.unix

Class Xargs

java.lang.Object

org.unix4j.unix.Xargs

public final class Xargs
extends Object

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

NAME

xargs - build and execute command lines from standard input

SYNOPSIS

	xargs
	xargs <args>
	xargs <delimiter>
	xargs <maxLines>
	xargs <maxArgs>
	xargs <maxLines> <maxArgs>
	xargs <delimiter> <maxLines>
	xargs <delimiter> <maxArgs>
	xargs <delimiter> <maxLines> <maxArgs>
	xargs <delimiter> <eof> <maxLines> <maxArgs>
	xargs [-zxrt]
	xargs [-zxrt] <delimiter>
	xargs [-zxrt] <maxLines>
	xargs [-zxrt] <maxArgs>
	xargs [-zxrt] <maxLines> <maxArgs>
	xargs [-zxrt] <delimiter> <maxLines>
	xargs [-zxrt] <delimiter> <maxArgs>
	xargs [-zxrt] <delimiter> <maxLines> <maxArgs>
	xargs [-zxrt] <delimiter> <eof> <maxLines> <maxArgs>

See Xargs.Interface for the corresponding command signature methods.

DESCRIPTION

The xargs utility reads items from the standard input, delimited by blanks (which can be protected with double or single quotes or a backslash) or newlines, and executes the command (default is /bin/echo) one or more times withany initial arguments followed by items read from standard input. Blank lines onthe standard input are ignored.

Because Unix filenames can contain blanks and newlines, this default behaviour is often problematic; filenames containing blanks and/or newlines are incorrectly processed by xargs. In these situations it is better to use the --null option, which prevents such problems. When using this option you will need to ensure that the program which produces the input for xargs also uses a null character as a separator. If that program is find for example, the --print0 option does this for you.If any invocation of the command exits with a status of 255, xargs will stop immediately without reading any further input. An error messageis issued on stderr when this happens.

Options

The following options are supported:

	-z		--delimiter0		Input items are terminated by a null character instead of by whitespace, and the quotes and backslash are not special (every character is taken literally). Disables the end of file string, which is treated like any other argument. Useful when input items might contain white space, quote marks, or backslashes. The find --print0 option produces input suitable for this mode. (This option is ignored if an explicit delimiter operand is specified).
	-x		--exactArgs		Terminate immediately if maxArgs is specified but the found number of variable items is less than maxArgs. (This option is ignored if no maxArgs operand is specified).
	-r		--noRunIfEmpty		If the standard input does not contain any nonblanks, do not run the command. Normally, the command is run once even if there is no input.
	-t		--verbose		Print the command line on the standard error output before executing it.

OPERANDS

The following operands are supported:

	<delimiter>	:	String		Input items are terminated by the specified characters.
	<eof>	:	String		If the end of file string occurs as a line of input, the rest of the input is ignored.
	<maxLines>	:	long		Use at most maxLines nonblank input lines per command invocation.
	<maxArgs>	:	int		Use at most maxArgs arguments per command invocation.
	<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 "--maxArgs" operand have to be prefixed with the operand name (e.g. "--maxLines" for a subsequent line count operand value).
	<options>	:	XargsOptions		The options defining command behavior.

Nested Class Summary

Nested Classes

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

Field Summary

Fields

Modifier and Type	Field and Description
static XargsFactory	Factory Singleton factory instance for the "xargs" command.
static String	NAME The "xargs" command name.
static XargsOptionSets	Options Options for the "xargs" command: z, x, r, t.

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 "xargs" command name.

See Also:

Constant Field Values

Options

public static final XargsOptionSets Options

Options for the "xargs" command: z, x, r, t.

	-z		--delimiter0		Input items are terminated by a null character instead of by whitespace, and the quotes and backslash are not special (every character is taken literally). Disables the end of file string, which is treated like any other argument. Useful when input items might contain white space, quote marks, or backslashes. The find --print0 option produces input suitable for this mode. (This option is ignored if an explicit delimiter operand is specified).
	-x		--exactArgs		Terminate immediately if maxArgs is specified but the found number of variable items is less than maxArgs. (This option is ignored if no maxArgs operand is specified).
	-r		--noRunIfEmpty		If the standard input does not contain any nonblanks, do not run the command. Normally, the command is run once even if there is no input.
	-t		--verbose		Print the command line on the standard error output before executing it.

Factory

public static final XargsFactory Factory

Singleton factory instance for the "xargs" command.