escape.c

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

int main(int argc, char ** argv) {
  char c = '\0';
  int i = 0;
  int j = 1;
  /* Do not care if no arguments are passed; escaped nothing is still nothing. */
  if (argc < 2) {
    return 0;
  }
  while (j < argc) {
    while (i < strlen(argv[j])) {
      c = argv[j][i];
      /* This switch has no breaks on purpose. */
      switch (c) {
      case ';':
      case '\'':
      case ' ':
      case '!':
      case '"':
      case '#':
      case '$':
      case '&':
      case '(':
      case ')':
      case '|':
      case '*':
      case ',':
      case '<':
      case '>':
      case '[':
      case ']':
      case '\\':
      case '^':
      case '`':
      case '{':
      case '}':
        putchar('\\');
      default:
        putchar(c);
      }
      i++;
    }
    j++;
    if (j < argc) {
      putchar(' ');
    }
    i = 0;
  }
  /* Newline at the end */
  putchar('\n');
  return 0;
}