Ok, let's see if this gets you started. I'm going to write this as mostly pseudocode comments. You get to fill in the code. 
my %session_hash;
my %departments;
# for each of the 6 session files,
#     open and read line-by-line
#         parse out user_id, session_id, dept_code
          $session_hash{$session_id} = $dept_code;
          $departments{$dept_code}++;
#
# for each apache log
#     open and read line-by-line
#         parse out session_id
#         append the line to the file associated with $session_hash{$s
+ession_id}

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If you have a relatively small number of departments (keys %departments), you can keep all the output files open for writing. Otherwise, you'll need to open for append each time you want to write a line of output. (You could also hold some number of lines in memory and write them out every so often, for a little less open and closing action.)

HTH.

The PerlMonk tr/// Advocate

In reply to Re^3: hash referencing...best approach? by Roy Johnson
in thread hash referencing...best approach? by Anonymous Monk

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