org.unix4j.unix

Class Grep

java.lang.Object

org.unix4j.unix.Grep

public final class Grep
extends Object

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

NAME

grep - print lines matching a pattern

SYNOPSIS

	grep <args>
	grep <regexp>
	grep <regexp> <files>
	grep <pattern>
	grep <pattern> <files>
	grep <pattern> <paths>
	grep [-ivFnclx] <regexp>
	grep [-ivFnclx] <pattern>
	grep [-ivFnclx] <regexp> <files>
	grep [-ivFnclx] <regexp> <paths>
	grep [-ivFnclx] <pattern> <files>
	grep [-ivFnclx] <pattern> <paths>

See Grep.Interface for the corresponding command signature methods.

DESCRIPTION

The grep utility searches the input, selecting lines matching a pattern; the types of patterns are controlled by the options specified.

By default, an input line is selected if any pattern, treated as an entire regular expression matches any part of the line excluding the terminating newline character(s). By default, each selected input line is written to the output.

Regular expression matching is based on text lines. Since newline character(s) separate or terminate patterns, regular expressions cannot contain newline character(s). Similarly, since patterns are matched against individual lines (excluding the terminating newline character(s)) of the input, there is no way for a pattern to match newline character(s) found in the input.

Regular expressions used in this command must be based on the Java regular expression syntax.

Options

The following options are supported:

	-i		--ignoreCase		Match lines ignoring the case when comparing the strings, also known from Unix with its acronym 'i'.
	-v		--invertMatch		Invert the match result, that is, a non-matching line is written to the output and a matching line is not. This option is also known from Unix with its acronym 'v'.
	-F		--fixedStrings		Use fixed-strings matching instead of regular expressions. This is usually faster than the standard regexp version. (This option is ignored if a pattern operand is specified instead of the regexp string).
	-n		--lineNumber		Prefix each line of output with the line number within its input file.
	-c		--count		Suppress normal output; instead print a count of matching lines for each input file. With the -v, --invertMatch option, count non-matching lines.
	-l		--matchingFiles		Suppress normal output; instead print the name of each input file from which output would normally have been printed. The scanning will stop on the first match.
	-x		--wholeLine		Select only those matches that exactly match the whole line excluding the terminating line ending. (This option is ignored if a pattern operand is specified instead of the regexp string).

OPERANDS

The following operands are supported:

	<regexp>	:	String		Lines will be printed which match the given regular expression. The regexp string is surrounded with ".*" on both sides unless the --wholeLine option is specified. If the --fixedStrings option is used, plain string comparison is used instead of regular expression matching.
	<pattern>	:	java.util.regex.Pattern		Lines will be printed which match the given pattern.
	<paths>	:	String...		Pathnames of the input files to be searched for the pattern; 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 searched for the pattern; 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 "--pattern" and "--paths" operands have to be prefixed with the operand name (e.g. "--files" for subsequent file operand values).
	<options>	:	GrepOptions		The options defining the types of patterns and command behavior.

Nested Class Summary

Nested Classes

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

Field Summary

Fields

Modifier and Type	Field and Description
static GrepFactory	Factory Singleton factory instance for the "grep" command.
static String	NAME The "grep" command name.
static GrepOptionSets	Options Options for the "grep" command: i, v, F, n, c, l, x.

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 "grep" command name.

See Also:

Constant Field Values

Options

public static final GrepOptionSets Options

Options for the "grep" command: i, v, F, n, c, l, x.

	-i		--ignoreCase		Match lines ignoring the case when comparing the strings, also known from Unix with its acronym 'i'.
	-v		--invertMatch		Invert the match result, that is, a non-matching line is written to the output and a matching line is not. This option is also known from Unix with its acronym 'v'.
	-F		--fixedStrings		Use fixed-strings matching instead of regular expressions. This is usually faster than the standard regexp version. (This option is ignored if a pattern operand is specified instead of the regexp string).
	-n		--lineNumber		Prefix each line of output with the line number within its input file.
	-c		--count		Suppress normal output; instead print a count of matching lines for each input file. With the -v, --invertMatch option, count non-matching lines.
	-l		--matchingFiles		Suppress normal output; instead print the name of each input file from which output would normally have been printed. The scanning will stop on the first match.
	-x		--wholeLine		Select only those matches that exactly match the whole line excluding the terminating line ending. (This option is ignored if a pattern operand is specified instead of the regexp string).

Factory

public static final GrepFactory Factory

Singleton factory instance for the "grep" command.