In this release, a new flag -I, --isolate has been added. If this flag is given, duplicates found within a directory tree given as a single argument are all counted as one. Hence, in the following example, only duplicates that exist both inside dir1 and dir2 will be reported:
$ echo "foo" > test/dir1/foo1
$ echo "foo" > test/dir1/foo2
$ fclones group --isolate test/dir1 test/dir2
# Report by fclones 0.16.0
# Timestamp: 2021-09-26 16:11:21.905 +0200
# Command: fclones group --isolate test/dir1 test/dir2
# Found 0 file groups
# 0 B (0 B) in 0 redundant files can be removed
$ echo "foo" > test/dir2/foo3
# Report by fclones 0.16.0
# Timestamp: 2021-09-26 16:12:03.224 +0200
# Command: fclones group --isolate test/dir1 test/dir2
# Found 1 file groups
# 8 B (8 B) in 2 redundant files can be removed
6109f093b3fd5eb1060989c990d1226f, 4 B (4 B) * 3:
/home/pkolaczk/Projekty/fclones/test/dir1/foo1
/home/pkolaczk/Projekty/fclones/test/dir1/foo2
/home/pkolaczk/Projekty/fclones/test/dir2/foo3
Additionally, the output has been made deterministic when option --hardlinks is set (patch by @th1000s).