Using IntelliJ to diff two arbitrary files

Question

I\'m really liking the IntelliJ diff tool. I\'m wondering if it is possible to use this tool to diff two arbitrary files. I.e. files NOT in an IntelliJ project. Just pick tw

Answer 1

Since 2018.2, IntelliJ has officially supported it:

For windows: Ctrl + Shift + A, then type "Open Blank Diff Window"

For Mac: Cmd + Shift + A then type "Open Blank Diff Window"

Answer 2

I have found even better way if you need to compare opened file with any arbitrary file on filesystem:

• Be in editor of the first file, let say A.java.
• Ctrl+Shift+A, you will see:
• Select second "Compare With..." option, you will get "Select path" dialog:
• Select any file on you hard drive and confirm it, you will get diff window:

Answer 3

In order to compare two files that both aren't in the project, the following works for me in IntelliJ IDEA Ultimate 14.1.7 on Windows:

1. Open the first file in the IDE (either by dragging from Windows Explorer into the window, or by File / Open).
2. In the view menu, choose "Compare With…"
3. In the "Select Path" dialog that appears, select the second file (either directly, or by dragging from Windows Explorer into the dialog).

It then opens up in the traditional file comparison pane. If you try to edit one of the files, it presents the usual "Are you sure you want to edit a file that's not in your project" dialog, which one can accept if that's what one is trying to do.

Answer 4

Found this command line:

on MacOSX: (IDEA EAP 11)

/Applications/IntelliJ\ IDEA\ 11.app/Contents/MacOS/idea diff /Users/ben75/file1.txt /Users/ben75/file2.txt

On MacOSX it can't run when IDEA (11) is open.

on Windows: (IDEA EAP 12)

"C:\Program Files (x86)\JetBrains\IntelliJ IDEA 12.0\bin\idea.exe" diff C:\Users\ben75\file1.txt C:\Users\ben75\file2.txt

It runs even if IDEA is already open.

I have trouble when trying to compare files with no extensions (or extensions that don't match )

Directly from IDEA (EAP 12)

Not so easy, but it works...

• File > Open... > select "file1.txt"
• File > Open... > select "file2.txt"
• Create a "Favorite list" and add both files to this favorite list. (to do this : ctrl+right-click on file name tab in the editor > add to favorite > select the favorite list just created - see screenshot)
• Finally, open the "Favorites" view (Alt+2 or click on it on the left or your IDEA windows).
• Select both files
• Right click : "compare two files" (or ctrl+D)