the "diamond" operator <> attempts to read a line from the file whose name you pass on the command line. (e.g. ./myscript.pl file.txt) If you pass more than one filename on the command line, it will loop over all the lines in each file.

If it runs out of command-line arguments and you try to read from it, then it attempts to read from STDIN (in this context, the keyboard). What your code is doing is reading in the file once, on the first pass. You think it's going to read it again when you say  while ( <> ) {, but what it's actually doing is attempting to read another file whose name was passed to it on the command line. But there is no such thing, so it just sits there expecting input from the keyboard (Control-D is the symbol for "end of file", so try hitting that a few times and see what happens).

Moral of the story: don't do it that way =) Loop through the file *once* and do all your counting on that one run through it.

HTH

perl -e 'print "How sweet does a rose smell? "; chomp ($n = <STDIN>); 
+$rose = "smells sweet to degree $n"; *other_name = *rose; print "$oth
+er_name\n"'
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