There are better ways of doing this, but yes, a script can change itself. Here is a self modifying script that keeps track of the number of times it is called. 
# Get current file name
$filename = __FILE__;

# get old UID stored after __END__
$uid = <DATA>;
chomp($uid);
print "This script has been run $uid times $/";

# increment UID
$uid++;

# open current running file
open(THIS_IN, $filename) or die "Could not open file";
@code = <THIS_IN>;
close (THIS_IN);

# Store new UID in last line of this code
$size = @code;
@code[$size-1]=$uid;

# open current running file
open(THIS_OUT,"> $filename") or die "Could not output to file";
print THIS_OUT @code;
close (THIS_OUT);
 
__END__
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This is presented mostly for interest, as I am from the school of thought that self-modification is bad. It can lead to some very hard to track down bugs.

In reply to A script can change itself by ktross
in thread can a script change itself? by deathbygoats

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