So here is what I have: This just appends the end of the file which is close but not what I need. I need to add fileA in the MIDDLE of FileB based on the search term "XYZ" There is a marker in the middle of the file which does not change. 
#!/usr/bun/perl
#------------------------------
# This script searches for "search"
# and adds lines from fileSource to fileOutput

use warnings;
use strict;

#use Fcntl (:flock :seek);

# Check
unless(-e $ARGV[0] || -e $ARGV[1]){
      print("Please Enter A Valid File Name\n");
   exit 1;
}
#if($ARGV[0] == "--help"){
#      print("Usage is:\n");
#      print("perl conference_add.pl <Source File> <Output File> <Sear
+ch String>");
#}

# assigns file path to local variables
my($fileSource) = $ARGV[0];
my($fileOutput) = $ARGV[1];
my(@inputLines);
# opens files for reading/writing
open(FILESOURCE, "<", $fileSource) || die("Can not open $fileSource $!
+");
open(FILEOUT, ">>", $fileOutput) || die ("Can not open $fileOutput $!"
+);

@inputLines = <FILESOURCE>;
print FILEOUT @inputLines;


close(FILESOURCE);
close(FILEOUT);

[download]

fileA: 
1
2
3
4
5

[download]

fileB 
a
b
c
d
SEARCHPATTERN
e
f
g
h
i

[download]

end result: 
a
b
c
d
SEARCHPATTERN
1
2
3
4
5
e
f
g
h
i

[download]
please help.

In reply to Modifying File in the Middle by PyrexKidd

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