source: vendor/perl/5.8.8/vos/mv-if-diff

: mv-if-diff file1 file2
: move file1 to file2 if file1 and file2 are different.

if test $# -lt 2 ; then
        echo "usage:  $0 file1 file2"
        echo "move file1 to file2 if file1 and file2 are different."
        exit 1
fi
if cmp $1 $2 >/dev/null 2>&1; then
        echo "File $2 not changed."
        rm -f $1
else
        rm -f $2
        mv $1 $2
fi