em bv I justed tested the if -t and it doesn't work, I got the messages in my log file here is the code a I used with a comment added 
# perl -le'print "\e]0;$ENV{HOST}\7" if -t'

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In reply to Re^4: system function adds spurious characters to log file by Anonymous Monk
in thread system function adds spurious characters to log file by Anonymous Monk

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