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54  * Portions of this software are based upon software originally written
55  * by Daniel F. Savarese. We appreciate his contributions.
56  */
57
58 import java.io.*;
59 import java.util.*;
60
61 import org.apache.oro.text.*;
62 import org.apache.oro.text.regex.*;
63
64 /**
65  * This is a no-frills implementation of grep using Perl regular expressions.
66  * You can easily add most of the options present in most grep versions by
67  * creating a MatchAction class or classes whose behavior varies based on
68  * the provided flags.
69  *
70  @author <a HREF="dfs@savarese.org">Daniel F. Savarese</a>
71  @version $Id: grep.java,v 1.1.1.1 2000/07/23 23:08:48 jon Exp $
72  */
73 public final class grep {
74   static int _file = 0;
75
76   // args[] is declared final so that Inner Class may reference it.
77 public static final void main(final String JavaDoc[] args) {
78     MatchActionProcessor processor = new MatchActionProcessor();
79
80     if(args.length < 2) {
81       System.err.println("Usage: grep <pattern> <filename>");
82       System.exit(1);
83     }
84
85     try {
86       if(args.length > 2) {
87     // Print filename before line if more than one file is specified.
88 // Rely on _file to point to current file being processed.
89 processor.addAction(args[0], new MatchAction() {
90       public void processMatch(MatchActionInfo info) {
91         info.output.println(args[_file] + ":" + info.line);
92       }
93     });
94       } else {
95     // We rely on the default action of printing matched
96 // lines to the given OutputStream
97 processor.addAction(args[0]);
98       }
99     } catch(MalformedPatternException e) {
100       System.err.println("Bad pattern.");
101       e.printStackTrace();
102       System.exit(1);
103     }
104
105     for(_file = 1; _file < args.length; _file++) {
106       try {
107     processor.processMatches(new FileInputStream(args[_file]), System.out);
108       } catch(IOException e) {
109     System.err.println("Error opening or reading " + args[_file]);
110     e.printStackTrace();
111     System.exit(1);
112       }
113     }
114   }
115
116 }
117
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