Print the IPs that exist in either A or B, but not both.

Aliases: --diff, --diff-next

This is a positional operation:

1. All files before --diff are merged into set A
2. All files after --diff are merged into set B
3. The output is (A - B) union (B - A) — the XOR of the two sets

Exit code: 0 if the sets are identical (no output), 1 if there are differences. This makes --diff useful in scripts to detect changes.

Compare two versions of a blocklist:

# before.txt            # after.txt
10.0.0.0/24             10.0.0.0/24
10.0.1.0/24             10.0.1.0/25      # shrunk
10.0.2.0/24             10.0.2.0/24
                         10.0.3.0/24      # added

$ iprange before.txt --diff after.txt
10.0.1.128/25
10.0.3.0/24

The output shows 10.0.1.128/25 (the upper half of the /24 that was shrunk to a /25) and 10.0.3.0/24 (newly added). The two entries that remained identical are excluded.

Exit code check:

$ iprange before.txt --diff after.txt
10.0.1.128/25
10.0.3.0/24
$ echo $?
1

$ iprange before.txt --diff before.txt
$ echo $?
0

Quiet mode — suppress output, only check exit code:

$ iprange before.txt --diff after.txt --quiet
$ echo $?
1