toys/echo.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * echo.c - echo supporting -n and -e.
   4  *
   5  * See http://www.opengroup.org/onlinepubs/009695399/utilities/echo.html
   6  */
   7
   8 #include "toys.h"
   9
  10 void echo_main(void)
  11 {
  12         int i = 0;
  13         char *arg, *from = "\\abfnrtv", *to = "\\\a\b\f\n\r\t\v";
  14
  15         for (;;) {
  16                 arg = toys.optargs[i];
  17                 if (!arg) break;
  18                 if (i++) xputc(' ');
  19
  20                 // Handle -e
  21
  22                 if (toys.optflags&2) {
  23                         int c, j = 0;
  24                         for (;;) {
  25                                 c = arg[j++];
  26                                 if (!c) break;
  27                                 if (c == '\\') {
  28                                         char *found;
  29                                         int d = arg[j++];
  30
  31                                         // handle \escapes
  32
  33                                         if (d) {
  34                                                 found = strchr(from, d);
  35                                                 if (found) c = to[found-from];
  36                                                 else if (d == 'c') goto done;
  37                                                 else if (d == '0') {
  38                                                         c = 0;
  39                                                         while (arg[j]>='0' && arg[j]<='7')
  40                                                                 c = (c*8)+arg[j++]-'0';
  41                                                 }
  42                                         }
  43                                 }
  44                                 xputc(c);
  45                         }
  46                 } else xprintf("%s", arg);
  47         }
  48
  49         // Output "\n" if no -n
  50         if (!(toys.optflags&1)) xputc('\n');
  51 done:
  52         xflush();
  53 }