readline/examples/hist_erasedups.c

   1 /* hist_erasedups -- remove all duplicate entries from history file */
   2
   3 /* Copyright (C) 2011 Free Software Foundation, Inc.
   4
   5    This file is part of the GNU Readline Library (Readline), a library for
   6    reading lines of text with interactive input and history editing.
   7
   8    Readline is free software: you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation, either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    Readline is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with Readline.  If not, see <http://www.gnu.org/licenses/>.
  20 */
  21 #ifndef READLINE_LIBRARY
  22 #define READLINE_LIBRARY 1
  23 #endif
  24
  25 #include <unistd.h>
  26 #include <stdlib.h>
  27 #include <stdio.h>
  28
  29 #ifdef READLINE_LIBRARY
  30 #  include "history.h"
  31 #else
  32 #  include <readline/history.h>
  33 #endif
  34
  35 #include <string.h>
  36
  37 #define STREQ(a, b) ((a)[0] == (b)[0] && strcmp(a, b) == 0)
  38 #define STREQN(a, b, n) ((n == 0) ? (1) \
  39                                   : ((a)[0] == (b)[0] && strncmp(a, b, n) == 0))
  40
  41 extern int history_offset;
  42
  43 static void
  44 usage()
  45 {
  46   fprintf (stderr, "hist_erasedups: usage: hist_erasedups [-t] [filename]\n");
  47   exit (2);
  48 }
  49
  50 int
  51 main (argc, argv)
  52      int argc;
  53      char **argv;
  54 {
  55   char *fn;
  56   int r;
  57
  58   while ((r = getopt (argc, argv, "t")) != -1)
  59     {
  60       switch (r)
  61         {
  62         case 't':
  63           history_write_timestamps = 1;
  64           break;
  65         default:
  66           usage ();
  67         }
  68     }
  69   argv += optind;
  70   argc -= optind;
  71
  72   fn = argc ? argv[0] : getenv ("HISTFILE");
  73   if (fn == 0)
  74     {
  75       fprintf (stderr, "hist_erasedups: no history file\n");
  76       usage ();
  77     }
  78
  79   if ((r = read_history (fn)) != 0)
  80     {
  81       fprintf (stderr, "hist_erasedups: read_history: %s: %s\n", fn, strerror (r));
  82       exit (1);
  83     }
  84
  85   hist_erasedups ();
  86
  87   if ((r = write_history (fn)) != 0)
  88     {
  89       fprintf (stderr, "hist_erasedups: write_history: %s: %s\n", fn, strerror (r));
  90       exit (1);
  91     }
  92
  93   exit (0);
  94 }
  95
  96 int
  97 hist_erasedups ()
  98 {
  99   int r, n;
 100   HIST_ENTRY *h, *temp;
 101
 102   using_history ();
 103   while (h = previous_history ())
 104     {
 105       r = where_history ();
 106       for (n = 0; n < r; n++)
 107         {
 108           temp = history_get (n+history_base);
 109           if (STREQ (h->line, temp->line))
 110             {
 111               remove_history (n);
 112               r--;                      /* have to get one fewer now */
 113               n--;                      /* compensate for above increment */
 114               history_offset--;         /* moving backwards in history list */
 115             }
 116         }
 117     }
 118   using_history ();
 119
 120   return r;
 121 }