A fairly common Perl idiom is: 
# Localize expression into $_ using a single-value 'for'.
# $_ is default for many Perl functions.
for ($some_very_long_expression_you_will_use_more_than_once) {
  die unless defined;
  die unless /^expected/;
  do_something($_);
  do_something_else($_);
}

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Your code becomes: 
for ( $hash1->{'a'}->{'b'}->{'c'} ) {
  $hash2->{'bob'} = $_ if defined;
}

[download]

In reply to Idiom: Localize with 'for' by Util
in thread re-using a hash reference (was: Mar) by Anonymous Monk

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