$ perl -e '$_="foo\n"; print "1=|$1|\n" if m/(fo.+?)$/s'
1=|foo|

$ perl -e '$_="foo\n"; print "1=|$1|\n" if m/(fo.+?)\z/s'
1=|foo
|

##</code><code>##

$ perl -e '$_="foo\nbar"; print "1=|$1|\n" if m/(fo.+?)$/s'
1=|foo
bar|

$ perl -e '$_="foo\nbar\n"; print "1=|$1|\n" if m/(fo.+?)$/s'
1=|foo
bar|

$ perl -e '$_="foo\nbar\n"; print "1=|$1|\n" if m/(fo.+?)\z/s'
1=|foo
bar
|