src/echo.c

   1 /* echo.c, taken from Bash.
   2 Copyright (C) 1987, 1989, 1991, 1992 Free Software Foundation, Inc.
   3
   4 This file is part of GNU Bash, the Bourne Again SHell.
   5
   6 Bash is free software; you can redistribute it and/or modify it under
   7 the terms of the GNU General Public License as published by the Free
   8 Software Foundation; either version 2, or (at your option) any later
   9 version.
  10
  11 Bash is distributed in the hope that it will be useful, but WITHOUT ANY
  12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14 for more details.
  15
  16 You should have received a copy of the GNU General Public License along
  17 with Bash; see the file COPYING.  If not, write to the Free Software
  18 Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */
  19
  20 #ifdef HAVE_CONFIG_H
  21 #if defined (CONFIG_BROKETS)
  22 /* We use <config.h> instead of "config.h" so that a compilation
  23    using -I. -I$srcdir will use ./config.h rather than $srcdir/config.h
  24    (which it would do because it found this file in $srcdir).  */
  25 #include <config.h>
  26 #else
  27 #include "config.h"
  28 #endif
  29 #endif
  30
  31 #include <stdio.h>
  32 #include <sys/types.h>
  33 #include "system.h"
  34
  35 /* echo [-neE] [arg ...]
  36 Output the ARGs.  If -n is specified, the trailing newline is
  37 suppressed.  If the -e option is given, interpretation of the
  38 following backslash-escaped characters is turned on:
  39         \a      alert (bell)
  40         \b      backspace
  41         \c      suppress trailing newline
  42         \f      form feed
  43         \n      new line
  44         \r      carriage return
  45         \t      horizontal tab
  46         \v      vertical tab
  47         \\      backslash
  48         \num    the character whose ASCII code is NUM (octal).
  49
  50 You can explicitly turn off the interpretation of the above characters
  51 on System V systems with the -E option.
  52 */
  53
  54 /* If defined, interpret backslash escapes if -e is given.  */
  55 #define V9_ECHO
  56
  57 /* If defined, interpret backslash escapes unless -E is given.
  58    V9_ECHO must also be defined.  */
  59 #define V9_DEFAULT
  60
  61 #if defined (V9_ECHO)
  62 #  if defined (V9_DEFAULT)
  63 #    define VALID_ECHO_OPTIONS "neE"
  64 #  else
  65 #    define VALID_ECHO_OPTIONS "ne"
  66 #  endif /* !V9_DEFAULT */
  67 #else /* !V9_ECHO */
  68 #  define VALID_ECHO_OPTIONS "n"
  69 #endif /* !V9_ECHO */
  70
  71 /* The name this program was run with. */
  72 char *program_name;
  73
  74 void parse_long_options ();
  75
  76 static void
  77 usage ()
  78 {
  79   fprintf (stderr, "Usage: %s [{--help,--version}] [-ne] [string ...]\n",
  80            program_name);
  81   exit (1);
  82 }
  83
  84 /* Print the words in LIST to standard output.  If the first word is
  85    `-n', then don't print a trailing newline.  We also support the
  86    echo syntax from Version 9 unix systems. */
  87 void
  88 main (argc, argv)
  89      int argc;
  90      char **argv;
  91 {
  92   int display_return = 1, do_v9 = 0;
  93
  94   program_name = argv[0];
  95
  96   parse_long_options (argc, argv, usage);
  97
  98 /* System V machines already have a /bin/sh with a v9 behaviour.  We
  99    use the identical behaviour for these machines so that the
 100    existing system shell scripts won't barf. */
 101 #if defined (V9_ECHO) && defined (V9_DEFAULT)
 102   do_v9 = 1;
 103 #endif
 104
 105   --argc;
 106   ++argv;
 107
 108   while (argc > 0 && *argv[0] == '-')
 109     {
 110       register char *temp;
 111       register int i;
 112
 113       /* If it appears that we are handling options, then make sure that
 114          all of the options specified are actually valid.  Otherwise, the
 115          string should just be echoed. */
 116       temp = argv[0] + 1;
 117
 118       for (i = 0; temp[i]; i++)
 119         {
 120           if (rindex (VALID_ECHO_OPTIONS, temp[i]) == 0)
 121             goto just_echo;
 122         }
 123
 124       if (!*temp)
 125         goto just_echo;
 126
 127       /* All of the options in TEMP are valid options to ECHO.
 128          Handle them. */
 129       while (*temp)
 130         {
 131           if (*temp == 'n')
 132             display_return = 0;
 133 #if defined (V9_ECHO)
 134           else if (*temp == 'e')
 135             do_v9 = 1;
 136 #if defined (V9_DEFAULT)
 137           else if (*temp == 'E')
 138             do_v9 = 0;
 139 #endif /* V9_DEFAULT */
 140 #endif /* V9_ECHO */
 141           else
 142             goto just_echo;
 143
 144           temp++;
 145         }
 146       argc--;
 147       argv++;
 148     }
 149
 150 just_echo:
 151
 152   if (argc > 0)
 153     {
 154 #if defined (V9_ECHO)
 155       if (do_v9)
 156         {
 157           while (argc > 0)
 158             {
 159               register char *s = argv[0];
 160               register int c;
 161
 162               while ((c = *s++))
 163                 {
 164                   if (c == '\\' && *s)
 165                     {
 166                       switch (c = *s++)
 167                         {
 168                         case 'a': c = '\007'; break;
 169                         case 'b': c = '\b'; break;
 170                         case 'c': display_return = 0; continue;
 171                         case 'f': c = '\f'; break;
 172                         case 'n': c = '\n'; break;
 173                         case 'r': c = '\r'; break;
 174                         case 't': c = '\t'; break;
 175                         case 'v': c = (int) 0x0B; break;
 176                         case '0': case '1': case '2': case '3':
 177                         case '4': case '5': case '6': case '7':
 178                           c -= '0';
 179                           if (*s >= '0' && *s <= '7')
 180                             c = c * 8 + (*s++ - '0');
 181                           if (*s >= '0' && *s <= '7')
 182                             c = c * 8 + (*s++ - '0');
 183                           break;
 184                         case '\\': break;
 185                         default:  putchar ('\\'); break;
 186                         }
 187                     }
 188                   putchar(c);
 189                 }
 190               argc--;
 191               argv++;
 192               if (argc > 0)
 193                 putchar(' ');
 194             }
 195         }
 196       else
 197 #endif /* V9_ECHO */
 198         {
 199           while (argc > 0)
 200             {
 201               fputs (argv[0], stdout);
 202               argc--;
 203               argv++;
 204               if (argc > 0)
 205                 putchar (' ');
 206             }
 207         }
 208     }
 209   if (display_return)
 210     putchar ('\n');
 211   exit (0);
 212 }