You are presumably trying to do this using `backtics`. Bacticks capture the scripts output into a variable. In fact the "hang" is the program you are running waiting patiently for your input (with the prompt captured by the backtics):

C:\>perl -e "print 'Hello '; system('date'); print 'world'";
Hello The current date is: Tue 17/06/2008
Enter the new date: (dd-mm-yy) 17-06-08
world
C:\>

C:\>perl -e "print 'Hello '; `date`; print 'world'";
Hello 18-06-08  <--- type in data here
world
C:\>date
The current date is: Wed 18/06/2008
[snip]

C:\>perl -e "print 'Hello '; $p = `date`; print $p.' world'";
Hello 17-08-08
The current date is: Tue 17/06/2008
Enter the new date: (dd-mm-yy)  world
C:\>
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