using command line switches to edit file

kitty has asked for the wisdom of the Perl Monks concerning the following question:

Hi,
My program asks the user to enter the name of the file and the parameter to be changed in that file from the command line.
$ perl comm.pl -f test-file -p <new value>

The test-file contents are of the form :

<PROP GUID="471138786526914052" EXPR="≪E The_Rounding_Unit=&Quot;1e-16&Quot; Absolute_Error_Tolerance=&Quot;1e-15&Quot; /&Gt";"/>

Iam posting a part of the code which replaces the old value 1e-16 (which is stored in this form &Quot;1e-16&Quot;) with the <new value> entered by the user and then renames the file with the timestamp. I can't figure out where iam going wrong. Does the command line accept more than 2 switches with values ? i have used Getopt::Long module. Please help me out.

if ($var{file}) #the test-file name entered by user
{
 my $fname=$var{file};
 unless ($fname) { die ("No file specified.\n"); }
 unless (-e $fname) { die ("File does not exist.\n");}
 my $line;
 open (INFO,"$fname") or die ("Cannot open .. $!\n");
 while (<INFO>)
{
  $line=<INFO>;
}  
close INFO;  
  my @new2;
  if($var{param}) { list_param($var{param}); }
  if($var{the})   { list_the($var{the}); }

sub list_param($)
{        
   if ($line =~ m:Absolute_Error_Tolerance=&quot:)
      {
          @new2=split(/\&quot;/,$line);
          $line=~s/$new2[1]/$G{param}/;
       }
}
sub list_the($)
{
      if ($line =~ m:The_Rounding_Unit=&quot:)
       {
          @new2=split(/\&quot;/,$line);
          $line=~s/$new2[1]/$G{the}/;
       }
}
my $timestamp = strftime("%m/%d/%Y_", localtime((stat($var{file}))[9])
+);
my $file2=$timestamp.$var{file};
rename ($var{file},$file2) or warn "***\n";
}
[download]

Comment on using command line switches to edit file Download Code

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Re: using command line switches to edit file by physi (Friar) on Feb 13, 2006 at 12:17 UTC
Hmm, don't really understand what you are doing there, but: `while (<INFO>) { $line=<INFO>; } close INFO; my @new2; if($var{param}) { list_param($var{param}); } if($var{the}) { list_the($var{the}); }` [download] You read in the whole file, and do nothing, but overwrite your $line. After theat you call yout sub's with the $line, which now contains only the last line of your inputfile. Maybe you should try to put the sub-calls into the while loop!? And if you want to replace everytime the same, than this maybe will work to: `perl -p -e 's/yourstring/yournewstring/g' inputfile > outputfile` [download] But that might not that flexible as you need... ----------------------------------- --the good, the bad and the physi-- -----------------------------------	[reply] [d/l] [select]
Re^2: using command line switches to edit file by kitty (Novice) on Feb 13, 2006 at 13:35 UTC
The test-file contents are of the form : <PROP GUID="471138786526914052" EXPR="≪E The_Rounding_Unit=&Quot;1e-16&Quot; Absolute_Error_Tolerance=&Quot;1e-15&Quot; /&Gt";"/> How do i extract the numerical values (in bold) from the above fileformat? I need to substitute it with the user input from the command line. `while (<INFO>) { @line=<INFO>; #will this help ? my @new2; if($var{param}) { list_param($var{param}); } if($var{the}) { list_the($var{the}); } sub list_param($) { if ($line =~ m:Absolute_Error_Tolerance=&quot:) { $line=$line1; @new2=split(/\"/,$line1); $line1=~s/$new2[1]/$G{param}/; } }` [download]	[reply] [d/l]
Re^3: using command line switches to edit file by holli (Abbot) on Feb 13, 2006 at 14:13 UTC
@line=<INFO>; #will this help ? Not at all. That construct will read the whole file into an array lines. That's not what you want here. Have a look at this code. `my $file = $ARGV[0]; my $repl = $ARGV[1]; open INFO, "<", $file or die $!; while (<INFO>) { s/(Absolute_Error_Tolerance=&Quot;)1e-15(&Quot)/$1$repl$2/; print; } close INFO;` [download] That can be easily made into a one-liner: `perl -n -e "s/(Absolute_Error_Tolerance=&Quot;)1e-15(&Quot)/$1$ARGV[0] +$2/; print;" filename` [download] just this doesn't work. You cannot pass additional variables into an -e "code" statement. However, you avoid problem by putting that line into a shell script or batchfile (here windows batchfile, as i have no idea of shell scripts). `@echo off perl -n -e "s/(Absolute_Error_Tolerance=&Quot;)1e-15(&Quot)/$1%2$2/; p +rint;" %1` [download] So you can then call that file using `batchfilename datafile replacement` [download] Note: The %1 and %2 are no perl hashes but variables from the shell. They get substituted by the command line values before! the script is run. holli, /regexed monk/	[reply] [d/l] [select]
Re^4: using command line switches to edit file by kitty (Novice) on Feb 13, 2006 at 16:53 UTC