post bits of code you like

i shall start:

open(F,"find -type f|");
while (<F>) {
 $_ = substr($_,2,-1);
 print "$_\n" if $v;
 push @{$dups{substr(`md5sum -b "$_"`,0,31)}}, $_;
}
close(F);

for every file in a directory it checksums the file, then adds the checksum as a key to a hash, the value being an array reference. the filename is then added to the array.

so basically the arrays have a list of files with the same checksum. i use this to find duplicates files.

Mail::RFC822::Address: regexp-based address validation

(?:(?:\r\n)?[ \t])*(?:(?:(?:[^()<>@,;:\\".[\] \000-\031]+(?:(?:(?:\r\n)?[ \t]
)+|\Z|(?=[["()<>@,;:\\".[\]]))|"(?:[^\"\r\\]|\\.|(?:(?:\r\n)?[ \t]))*"(?:(?:
\r\n)?[ \t])*)(?:\.(?:(?:\r\n)?[ \t])*(?:[^()<>@,;:\\".[\] \000-\031]+(?:(?:(
?:\r\n)?[ \t])+|\Z|(?=[["()<>@,;:\\".[\]]))|"(?:[^\"\r\\]|\\.|(?:(?:\r\n)?[
\t]))*"(?:(?:\r\n)?[ \t])*))*@(?:(?:\r\n)?[ \t])*(?:[^()<>@,;:\\".[\] \000-\0
31]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[["()<>@,;:\\".[\]]))|[([^[\]\r\\]|\\.)*\
](?:(?:\r\n)?[ \t])*)(?:\.(?:(?:\r\n)?[ \t])*(?:[^()<>@,;:\\".[\] \000-\031]+
(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[["()<>@,;:\\".[\]]))|[([^[\]\r\\]|\\.)*\](?:
(?:\r\n)?[ \t])*))*|(?:[^()<>@,;:\\".[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z
|(?=[["()<>@,;:\\".[\]]))|"(?:[^\"\r\\]|\\.|(?:(?:\r\n)?[ \t]))*"(?:(?:\r\n)
?[ \t])*)*\<(?:(?:\r\n)?[ \t])*(?:@(?:[^()<>@,;:\\".[\] \000-\031]+(?:(?:(?:\
r\n)?[ \t])+|\Z|(?=[["()<>@,;:\\".[\]]))|[([^[\]\r\\]|\\.)*\](?:(?:\r\n)?[
 \t])*)(?:\.(?:(?:\r\n)?[ \t])*(?:[^()<>@,;:\\".[\] \000-\031]+(?:(?:(?:\r\n)
?[ \t])+|\Z|(?=[["()<>@,;:\\".[\]]))|[([^[\]\r\\]|\\.)*\](?:(?:\r\n)?[ \t]
)*))*(?:,@(?:(?:\r\n)?[ \t])*(?:[^()<>@,;:\\".[\] \000-\031]+(?:(?:(?:\r\n)?[
 \t])+|\Z|(?=[["()<>@,;:\\".[\]]))|[([^[\]\r\\]|\\.)*\](?:(?:\r\n)?[ \t])*
)(?:\.(?:(?:\r\n)?[ \t])*(?:[^()<>@,;:\\".[\] \000-\031]+(?:(?:(?:\r\n)?[ \t]
)+|\Z|(?=[["()<>@,;:\\".[\]]))|[([^[\]\r\\]|\\.)*\](?:(?:\r\n)?[ \t])*))*)
*:(?:(?:\r\n)?[ \t])*)?(?:[^()<>@,;:\\".[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+
|\Z|(?=[["()<>@,;:\\".[\]]))|"(?:[^\"\r\\]|\\.|(?:(?:\r\n)?[ \t]))*"(?:(?:\r
\n)?[ \t])*)(?:\.(?:(?:\r\n)?[ \t])*(?:[^()<>@,;:\\".[\] \000-\031]+(?:(?:(?:
\r\n)?[ \t])+|\Z|(?=[["()<>@,;:\\".[\]]))|"(?:[^\"\r\\]|\\.|(?:(?:\r\n)?[ \t
]))*"(?:(?:\r\n)?[ \t])*))*@(?:(?:\r\n)?[ \t])*(?:[^()<>@,;:\\".[\] \000-\031
]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[["()<>@,;:\\".[\]]))|[([^[\]\r\\]|\\.)*\](
?:(?:\r\n)?[ \t])*)(?:\.(?:(?:\r\n)?[ \t])*(?:[^()<>@,;:\\".[\] \000-\031]+(?
:(?:(?:\r\n)?[ \t])+|\Z|(?=[["()<>@,;:\\".[\]]))|[([^[\]\r\\]|\\.)*\](?:(?
:\r\n)?[ \t])*))*\>(?:(?:\r\n)?[ \t])*)|(?:[^()<>@,;:\\".[\] \000-\031]+(?:(?
:(?:\r\n)?[ \t])+|\Z|(?=[["()<>@,;:\\".[\]]))|"(?:[^\"\r\\]|\\.|(?:(?:\r\n)?
[ \t]))*"(?:(?:\r\n)?[ \t])*)*:(?:(?:\r\n)?[ \t])*(?:(?:(?:[^()<>@,;:\\".[\]
\000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[["()<>@,;:\\".[\]]))|"(?:[^\"\r\\]|
\\.|(?:(?:\r\n)?[ \t]))*"(?:(?:\r\n)?[ \t])*)(?:\.(?:(?:\r\n)?[ \t])*(?:[^()<>
@,;:\\".[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[["()<>@,;:\\".[\]]))|"
(?:[^\"\r\\]|\\.|(?:(?:\r\n)?[ \t]))*"(?:(?:\r\n)?[ \t])*))*@(?:(?:\r\n)?[ \t]
)*(?:[^()<>@,;:\\".[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[["()<>@,;:\\
".[\]]))|[([^[\]\r\\]|\\.)*\](?:(?:\r\n)?[ \t])*)(?:\.(?:(?:\r\n)?[ \t])*(?
:[^()<>@,;:\\".[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[["()<>@,;:\\".[
\]]))|[([^[\]\r\\]|\\.)*\](?:(?:\r\n)?[ \t])*))*|(?:[^()<>@,;:\\".[\] \000-
\031]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[["()<>@,;:\\".[\]]))|"(?:[^\"\r\\]|\\.|(
?:(?:\r\n)?[ \t]))*"(?:(?:\r\n)?[ \t])*)*\<(?:(?:\r\n)?[ \t])*(?:@(?:[^()<>@,;
:\\".[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[["()<>@,;:\\".[\]]))|[([
^[\]\r\\]|\\.)*\](?:(?:\r\n)?[ \t])*)(?:\.(?:(?:\r\n)?[ \t])*(?:[^()<>@,;:\\"
.[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[["()<>@,;:\\".[\]]))|[([^[\
]\r\\]|\\.)*\](?:(?:\r\n)?[ \t])*))*(?:,@(?:(?:\r\n)?[ \t])*(?:[^()<>@,;:\\".\
[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[["()<>@,;:\\".[\]]))|[([^[\]\
r\\]|\\.)*\](?:(?:\r\n)?[ \t])*)(?:\.(?:(?:\r\n)?[ \t])*(?:[^()<>@,;:\\".[\]
\000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[["()<>@,;:\\".[\]]))|[([^[\]\r\\]
|\\.)*\](?:(?:\r\n)?[ \t])*))*)*:(?:(?:\r\n)?[ \t])*)?(?:[^()<>@,;:\\".[\] \0
00-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[["()<>@,;:\\".[\]]))|"(?:[^\"\r\\]|\\
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;:\\".[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[["()<>@,;:\\".[\]]))|"(?
:[^\"\r\\]|\\.|(?:(?:\r\n)?[ \t]))*"(?:(?:\r\n)?[ \t])*))*@(?:(?:\r\n)?[ \t])*
(?:[^()<>@,;:\\".[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[["()<>@,;:\\".
[\]]))|[([^[\]\r\\]|\\.)*\](?:(?:\r\n)?[ \t])*)(?:\.(?:(?:\r\n)?[ \t])*(?:[
^()<>@,;:\\".[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[["()<>@,;:\\".[\]
]))|[([^[\]\r\\]|\\.)*\](?:(?:\r\n)?[ \t])*))*\>(?:(?:\r\n)?[ \t])*)(?:,\s*(
?:(?:[^()<>@,;:\\".[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[["()<>@,;:\\
".[\]]))|"(?:[^\"\r\\]|\\.|(?:(?:\r\n)?[ \t]))*"(?:(?:\r\n)?[ \t])*)(?:\.(?:(
?:\r\n)?[ \t])*(?:[^()<>@,;:\\".[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[
["()<>@,;:\\".[\]]))|"(?:[^\"\r\\]|\\.|(?:(?:\r\n)?[ \t]))*"(?:(?:\r\n)?[ \t
])*))*@(?:(?:\r\n)?[ \t])*(?:[^()<>@,;:\\".[\] \000-\031]+(?:(?:(?:\r\n)?[ \t
])+|\Z|(?=[["()<>@,;:\\".[\]]))|[([^[\]\r\\]|\\.)*\](?:(?:\r\n)?[ \t])*)(?
:\.(?:(?:\r\n)?[ \t])*(?:[^()<>@,;:\\".[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+|
\Z|(?=[["()<>@,;:\\".[\]]))|[([^[\]\r\\]|\\.)*\](?:(?:\r\n)?[ \t])*))*|(?:
[^()<>@,;:\\".[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[["()<>@,;:\\".[\
]]))|"(?:[^\"\r\\]|\\.|(?:(?:\r\n)?[ \t]))*"(?:(?:\r\n)?[ \t])*)*\<(?:(?:\r\n)
?[ \t])*(?:@(?:[^()<>@,;:\\".[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[["
()<>@,;:\\".[\]]))|[([^[\]\r\\]|\\.)*\](?:(?:\r\n)?[ \t])*)(?:\.(?:(?:\r\n)
?[ \t])*(?:[^()<>@,;:\\".[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[["()<>
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;:\\".[\]]))|[([^[\]\r\\]|\\.)*\](?:(?:\r\n)?[ \t])*)(?:\.(?:(?:\r\n)?[ \t]
)*(?:[^()<>@,;:\\".[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[["()<>@,;:\\
".[\]]))|[([^[\]\r\\]|\\.)*\](?:(?:\r\n)?[ \t])*))*)*:(?:(?:\r\n)?[ \t])*)?
(?:[^()<>@,;:\\".[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[["()<>@,;:\\".
[\]]))|"(?:[^\"\r\\]|\\.|(?:(?:\r\n)?[ \t]))*"(?:(?:\r\n)?[ \t])*)(?:\.(?:(?:
\r\n)?[ \t])*(?:[^()<>@,;:\\".[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[[
"()<>@,;:\\".[\]]))|"(?:[^\"\r\\]|\\.|(?:(?:\r\n)?[ \t]))*"(?:(?:\r\n)?[ \t])
*))*@(?:(?:\r\n)?[ \t])*(?:[^()<>@,;:\\".[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])
+|\Z|(?=[["()<>@,;:\\".[\]]))|[([^[\]\r\\]|\\.)*\](?:(?:\r\n)?[ \t])*)(?:\
.(?:(?:\r\n)?[ \t])*(?:[^()<>@,;:\\".[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z
|(?=[["()<>@,;:\\".[\]]))|[([^[\]\r\\]|\\.)*\](?:(?:\r\n)?[ \t])*))*\>(?:(
?:\r\n)?[ \t])*))*)?;\s*)