JabRef lets you link up your entries with PDF or PS files stored on your system, as well as links to the document on the web in the form of an URL or a DOI identifier.
To change the external viewer settings, go to Options -> Preferences -> External programs.
By default the entry table will contain two columns with icons for those entries that link to external files and URLs. You can disable any of these in Preferences -> Table. The second column of the entry table shows icons for PDF or PS files (only PDF if both are present), and the third column shows icons for URL or DOI (only URL if both are present). You open the file or web page by clicking on an icon.
Note: If the PS field does not appear in the entry editor (in the 'General' panel), you may have to customize the entry types of the general fields.
Additionally, if you give your PDF and PS files names that correspond to the relevant entry's bibtex key (plus '.pdf' or '.ps'), JabRef will be able to search your main directories and its subfolders for the correct PDF and PS. Once the correctly-named PDF or PS is in place you access this function by clicking the 'Auto' button next to the PDF and PS fields in the entry editor. If the PDF or PS is found, the field will immediately be set.
If you name a PDF or PS file as mentioned, you can also open the file without setting the PDF or PS field of the entry at all. The downside is that the PDF or PS icon will not appear in the table unless you do (manually or with the 'Auto' button).
You can set PDF and PS directories specific to a database (File -> Database properties). These directories will supersede the main directories.
In the previous sections JabRef's auto-linking feature was described: If you choose names for your files corresponding to the bibtex-key + plus the extension, JabRef will automatically be able to find it.
Since JabRef 2.2 it is now possible to have greater flexibility in the naming scheme by using regular expression for the search. In most cases it should not be necessary though to adapt the given default.
If you open the external preferences (Options -> Preferences -> External Programs) you will find an option called "Use Regular Expression Search". Checking this option will allow you to enter your own regular expression for search in the PDF directories.
The following syntax is understood:
*- Search in all immediate all subdirectories excluding the current and any deeper subdirectories.
**- Search in all subdirectories recursively AND the current directory.
..- The current directory and the parent directory.
[title]- All expressions in square brackets are replace by the corresponding field in the current entry
[extension]- Is replaced by the file-extension of the field you are using.
The default for searches is
**/.*[bibtexkey].*\\.[extension]. As you can see this will
search in all subdirectories of the extension-based directory (for instance in the PDF directory) for any file that has the correct extension and
contains the Bibtex-key somewhere.