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$$ value changes often

 
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# 1  
Old 06-21-2012
$$ value changes often
May i know why $$ changes often?
Code:
bash-2.05b$ perl -e'print "$$\n"'                                                                                          
4444236
bash-2.05b$ echo $$
4100348
bash-2.05b$ perl -e'print "$$\n"'
4431936
bash-2.05b$ echo $$;perl -e'print "$$\n"'
4100348
4268078

Thanks
# 2  
Old 06-21-2012
Notice that 4100348 does not change, as this is your current shell. The other numbers are the PID or the various perl interpreter processes that get started..
# 3  
Old 06-21-2012
try this for current shell pid
Code:
typeset -x x=$$ ; perl -e 'print "$ENV{x}\n"'

 
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