Search and Replace line by line not working on Filehandle

matze77 has asked for the wisdom of the Perl Monks concerning the following question:

Update: i Could break down the lengthy question to a simple:
How to overwrite a given line in a file with another line without appending?.

#!/usr/bin/perl
use strict;
use File::Copy;
use warnings;
my $open_file= "C:/oracle/ora81/network/ADMIN/SQLNET.ORA";
my $write_file=">>C:/oracle/ora81/network/ADMIN/SQLNET.ORA";
open(IN,$open_file) || die "cannot open $open_file $!";
open(OUT,$write_file) || die "cannot create $write_file $!";
while (<IN>) {
  if ($_ = /^SQLNET\.AUTHENTICATION_SERVICES=\ \(NTS\)$/){
    print  "\#\ ^SQLNET\.AUTHENTICATION_SERVICES=\ (NTS)";
    print OUT $_  "\#\ SQLNET\.AUTHENTICATION_SERVICES=\ (NTS)";
#Want to write the 2nd string print ... to OUT write handle  
#OUT $_
  }
}
[download]

I want the print state in the while loop to write to the OUT Filehandle, i got a syntax error if i try this? Any Ideas where my error is? error message:

String found where operator expected at ora.pl line 22, near "$_  "\#\
+ SQLNET\.AUTHENTICATION_SERVICES=\ (NTS)""
    (Missing operator before "\#\ SQLNET\.AUTHENTICATION_SERVICES=\ (N
+TS)"?)
syntax error at ora.pl line 22, near "$_  "\#\ SQLNET\.AUTHENTICATION_
+SERVICES=\ (NTS)""
Execution of ora.pl aborted due to compilation errors.
[download]

Thanks
MH

Comment on Search and Replace line by line not working on Filehandle Select or Download Code

Replies are listed 'Best First'.
Re: Search and Replace line by line not working on Filehandle by cdarke (Prior) on Jan 15, 2010 at 11:06 UTC
May I suggest that you need to create a new file, commenting out the required line/s, then rename it? For example: `use warnings; use strict; my $filename = 'C:/oracle/ora81/network/ADMIN/SQLNET.ORA'; open (my $in, '<', $filename) \|\| die "Unable to open $filename:$!"; open (my $out,'>', "$filename.tmp") \|\| die "Unable to open $filename.t +mp:$!"; while (<$in>) { # Identify the record if ($_ eq "SQLNET.AUTHENTICATION_SERVICES= (NTS)\n"){ $_ = '# '.$_; } print $out $_; } close $in; close $out; rename "$filename.tmp",$filename or die "Unable to rename: $!";` [download]	[reply] [d/l]
Re^2: Search and Replace line by line not working on Filehandle by matze77 (Friar) on Jan 15, 2010 at 13:24 UTC
Yes. Your suggestions are always welcome. Thanks that works fine and shows me another (which i think easier to understand way than my solution) which helps me on my way to the intermediate beginner ... Thanks MH	[reply]
Re: substitute on file line by line not working syntax error by Ratazong (Monsignor) on Jan 15, 2010 at 08:27 UTC
print OUT $_ "\#\ SQLNET\.AUTHENTICATION_SERVICES=\ (NTS)"; Isn't there a comma missing between $_ and "\#SQL..."? Rata	[reply]
Re: substitute on file line by line not working syntax error by ikegami (Patriarch) on Jan 15, 2010 at 08:31 UTC
What's `$_ "\#\ SQLNET\.AUTHENTICATION_SERVICES=\ (NTS)"` [download] suppose to do? Are you missing a comma?	[reply] [d/l]
Re^2: substitute on file line by line not working syntax error by matze77 (Friar) on Jan 15, 2010 at 08:47 UTC
changed this the comma was missing: `print OUT $_ , "\#\ SQLNET\.AUTHENTICATION_SERVICES=\ (NTS)";` [download] OK. Now the line prints, i wanted it to overwrite the original line but it prints to the next line maybe i need to "remember" the line number and overwrite it? result: `SQLNET.AUTHENTICATION_SERVICES= (NTS) 1# SQLNET.AUTHENTICATION_SERVICES= (NTS)<p>` [download] Are the parentheses around (NTS) interpreted as "backreference" and printed before as 1 ...? Thanks MH	[reply] [d/l] [select]
Re^3: substitute on file line by line not working syntax error by ikegami (Patriarch) on Jan 15, 2010 at 09:03 UTC
If you want just the new line, not the old and the new one, don't print the old one ($_).	[reply]
Re^4: substitute on file line by line not working syntax error by matze77 (Friar) on Jan 15, 2010 at 09:39 UTC
Re^5: substitute on file line by line not working syntax error by cdarke (Prior) on Jan 15, 2010 at 10:52 UTC
Some notes below your chosen depth have not been shown here
Re^2: substitute on file line by line not working syntax error by matze77 (Friar) on Jan 15, 2010 at 08:41 UTC
original file: `# SQLNET.ORA Network Configuration File: c:\oracle\ora81\network\admin +\sqlnet.ora # Generated by Oracle configuration tools. NAMES.DEFAULT_DOMAIN = world SQLNET.AUTHENTICATION_SERVICES= (NTS) NAMES.DIRECTORY_PATH= (TNSNAMES) SQLNET.AUTHENTICATION_SERVICES= (NTS)<p>` [download] The Line SQLNET.AUTHENTICATION_SERVICES= (NTS) needs to be commented/deactived so afterwards it reads: `# Generated by Oracle configuration tools. ... # SQLNET.AUTHENTICATION_SERVICES= (NTS) ...` [download] <id://> Thanks MH	[reply] [d/l] [select]
Re: Search and Replace line by line not working on Filehandle by bv (Friar) on Jan 15, 2010 at 15:23 UTC
In case you were looking for another solution, you could use Tie::File, then loop over the tied array `print map{substr'hark, suPerJacent other l',$_,1}(11,7,6,16,5,1,15,18..23,8..10,24,17,0,12,13,3,14,2,4);`	[reply] [d/l]