#!/usr/bin/perl
###############################################################################
#
# name:       strSub.pl
#
# usage:      strSub.pl -fht <from str1|txt1> <to str2|txt2> <file1> 
#                      [<file2> ... <fileN>]
#
# decription: substitute <str1> with <str2> in all files.
#             with option -f the script will work like a generic multilines
#             text substitution, <str1> and <str2> will be loaded from the
#             files <txt1> and <txt2>.
#
# author:     paolo guiducci
#
# Disclaimer: You are free to use this code, being understood that I decline
#             any responsibility, direct or implied, for damages or 
#             inconveniences that its use or impossibility of use may cause
#             (directly or indirectly). If your local law does not allow a full
#             decline of responsibility by the author of a software that you
#             use, then you are not allowed to use this code or any part of it. 
#
# web:        http://pguiducci.com
###############################################################################


use Getopt::Std;

getopts("fht") or usage();

if ($opt_h) {usage()};

my $par1 = shift(@ARGV);
my $par2 = shift(@ARGV);
my $str1;
my $str2;
my @par;
my $fl=0;
my $ind=0;

if ($opt_f) {
   open (PAR, "<$par1") or die "unable to open $par1";
   @par = <PAR>;
   $str1 = join("",@par);
   chomp($str1);
   close PAR;
   open (PAR, "<$par2") or die "unable to open $par2";
   @par = <PAR>;
   $str2 = join("",@par);
   chomp($str2);
   close PAR;
} else {
   $str1=$par1;
   $str2=$par2;
}
   

foreach $file (@ARGV) {
   if (!-w $file) {
      print "warning: $file is not writable";
      next;
   }
   open (IN, "< $file") or die "unable to open $file";
   @fileIn = <IN>;
   close IN;

   $fileSca = join("",@fileIn);
   $fileOut = $fileSca;
   $fileOut =~ s/$str1/$str2/g;
   
   if ($fileOut ne $fileSca) {
      if ($opt_t) {
         print "test update file: $file\n";
      } else {
         open (OUT, "> $file") or die "unable to open $file in output mode";
         print OUT $fileOut;
         close OUT;
         print "updated file: $file\n";
      }
   } else {
      print "file not updated: $file\n";
   }   
}


sub usage {
   print "usage: strSub.pl -fht <from str1|txt1> <to str2|txt2> <file1> [<file2> ... <fileN>]\n";
   exit;
}