say "sed -ie 's/\(.*\)/Number => \1/' test.txt"; say qq{sed -ie 's/\(.*\)/Number => \1/' test.txt}; say q{sed -ie 's/\(.*\)/Number => \1/' test.txt}; __END__ sed -ie 's/(.*)/Number => /' test.txt sed -ie 's/(.*)/Number => /' test.txt sed -ie 's/\(.*\)/Number => \1/' test.txt