Show them Perl's greatest asset -- concise solutions to everyday problems.

If you have time, pick some task that will resonate with as many of them as possible and get one or more of them to solve the chosen task in their favoured langugages before the day.

By way of example (because the examples already exist): frequency count the words in a text file.

• C (211 lines):
  <Reveal this spoiler or all spoilers in this node or all in this thread>
• C++ (79 lines):

  // -*- mode: c++ -*-
  // $Id: wordfreq.g++,v 1.5 2001/07/21 23:51:05 doug Exp $
  // http://www.bagley.org/~doug/shootout/
  // By Tamás Benkő
  
  #include <cstdio>
  #include <cctype>
  #include <cstring>
  #include <ext/hash_map>
  #include <vector>
  #include <algorithm>
  
  using namespace std;
  
  int const bufsize = 4096;
  int const wsize = 64;
  
  class word_reader
  {
      int ws;
      char buf[bufsize+1], *bptr, *word;
      FILE *input;
  
      bool fill();
  
  public:
      word_reader(FILE *i): ws(wsize), bptr(buf), word(new char[ws+1]), 
  +input(i)
      {*bptr = *word = '\0';}
      int operator()(char const **);
  };
  
  inline bool word_reader::fill()
  {
      int nread = fread(buf, sizeof(char), bufsize, input);
      buf[nread] = '\0';
      bptr = buf;
      return nread > 0;
  }
  
  int word_reader::operator()(char const **w)
  {
      int len = 0;
      char c;
      while (*bptr || fill()) {
      if (isalpha(c = *bptr++)) {
          word[len] = tolower(c);
          if (++len == ws) {
          char *nword = new char[(ws *= 2)+1];
          memcpy(nword, word, len);
          delete[] word;
          word = nword;
          }
      }
      else if (len > 0) break;
      }
      *w = word;
      word[len] = '\0';
      return len;
  }
  
  typedef hash_map<char const *, int> counter;
  typedef pair<char const *, int> hpair;
  
  namespace std
  {
      inline bool operator<(hpair const &lhs, hpair const &rhs)
      {
      return lhs.second != rhs.second ? lhs.second > rhs.second
          : strcmp(lhs.first, rhs.first) > 0;
      }
  
      template<> struct equal_to<char const *>
      {
      bool operator()(char const *s1, char const *s2) const
          {return strcmp(s1, s2) == 0;}
      };
  }
  
  int main()
  {
      int len;
      const char *w;
      counter hist;
      word_reader wr(stdin);
  
      while ((len = wr(&w)) > 0) {
      counter::iterator i = hist.find(w);
      if (i == hist.end()) hist[strcpy(new char[len+1], w)] = 1;
      else ++i->second;
      }
  
      vector<hpair> v(hist.begin(), hist.end());
      sort(v.begin(), v.end());
      for (size_t i = 0; i < v.size(); ++i)
      printf("%7d\t%s\n", v[i].second, v[i].first);
  
      return 0;
  }
  [download]

• Java (68 lines):
  <Reveal this spoiler>
• Python (24 lines):
  <Reveal this spoiler>
• Haskell (20 lines):
  <Reveal this spoiler>

And then write & run your perl solution in real time:

perl -nle"y/a-zA-Z/ /cs; ++$h{$_} for split }{ print qq[$_:$h{$_}] for
+ sort keys %h" theFile
break:1
brief:1
bring:3
brought:2
buffalo:16
burden:1
but:20
by:16
call:2
called:6
came:2
campaign:1
can:36
cannot:2
capable:1
capitals:1
career:2
cart:1
case:2
...
[download]