linux/debian/bin/fix-shebang

#!/usr/bin/perl -pi

# Change "#!/usr/bin/env perl" to "#!/usr/bin/perl" (policy §10.4).
# Other uses of /usr/bin/env should probably be converted as well, but
# policy doesn't specify what to do.
if ($. == 1 && m|^\#!\s*/usr/bin/env\s+(.+)|) {
    if ($1 eq "perl") {
        $_ = "#!/usr/bin/perl\n";
    } else {
        print STDERR "W: Found #!/usr/bin/env $1 and don't know what to substitute\n";
    }
}