Try the abbrev-mode. Here is the sample code that you can stick in an .emacs file, which enables the abbrev-mode and sets up some global abbreviations:

(abbrev-mode 1)
(define-abbrev-table 'global-abbrev-table '(
    ("dbg" "use Data::Dumper qw( Dumper );^Mwarn Dumper[];^[hi" nil 1)
    ))
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I found that it is better to add a hook to the preferred editing made, to enable abbreviation mode, like:

(add-hook 'text-mode-hook (lambda () (abbrev-mode 1)))
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This enables the abbreviation mode while editing text files. Also you can enbale the abbrev mode by typing: M-x abbrev-mode