$ perl pdf2john.pl file.pdf
Can't locate ExifTool.pm in @INC (you may need to install the ExifTool module) (@INC contains: ./lib /etc/perl /usr/local/lib64/perl5/5.26.2/x86_64-linux /usr/local/lib64/perl5/5.26.2 /usr/lib64/perl5/vendor_perl/5.26.2/x86_64-linux /usr/lib64/perl5/vendor_perl/5.26.2 /usr/local/lib64/perl5 /usr/lib64/perl5/vendor_perl /usr/lib64/perl5/5.26.2/x86_64-linux /usr/lib64/perl5/5.26.2) at pdf2john.pl line 39.
BEGIN failed--compilation aborted at pdf2john.pl line 39.