Change metadata in PDF file using exiftool

To change the metadata in PDF files, use a command line tool called exiftool. This tool can manipulate metadata in many file types, but in this post we will focus on changing the metadata in a pdf file.

To install this tool in ubuntu, run below command

$ sudo apt install libimage-exiftool-perl -y

Then, use the exiftool command to list out all the metadata in a pdf file

$ exiftool mypdf.pdf

Some details like below will be shown

ExifTool Version Number         : 11.88

File Name                       : mypdf.pdf

Directory                       : .

File Size                       : 1 MB

File Modification Date/Time     : 2022:12:08 07:46:39+08:00

File Access Date/Time           : 2022:12:08 07:46:43+08:00

File Inode Change Date/Time     : 2022:12:08 07:46:39+08:00

File Permissions                : rw-rw-r--

File Type                       : PDF

File Type Extension             : pdf

MIME Type                       : application/pdf

PDF Version                     : 1.3

Linearized                      : No

Page Count                      : 15

XMP Toolkit                     : Image::ExifTool 11.88

Title                           : mypdf.pdf

Producer                        : Nitro PDF PrimoPDF

Create Date                     : 2022:09:30 16:57:06-08:00

Modify Date                     : 2022:09:30 16:57:06-08:00

Creator                         : PrimoPDF http://www.primopdf.com

Author                          : andre

To see just one tag, we can specify it when running exiftool. Let's say I want to see just the Author

$ exiftool -Author mypdf.pdf

Author                          : andre

To change the value of the tag, just provide the new value to the tag in the exiftool command. Let's say I want to change the author from andre to john

$ exiftool -Author=john mypdf.pdf

We can verify that the change has been implemented

$ exiftool -Author mypdf.pdf

Author                          : john

Once we are satisfied with the change, delete the original backup file that exiftool created prior to changing the metadata

$ rm mypdf.pdf_original