Currently, we use "ls ... | sort -R | head -n1" (or tail) to choose a random file in a directory.It sorts the files with "ls", sort it randomly and pick the first line, which wastes the "ls" sort. Also, using "sort -R | head -n1" is inefficient. Furthermore, even without "head" or "tail", "shuf" is faster than "sort -R". This series introduces a new helper _random_file() to choose a file in a directory randomly. Also, replace "sort -R" with _random_file() or "shuf". Naohiro Aota (3): common/rc: introduce _random_file() helper fstests/btrfs: use _random_file() helper btrfs/004: use shuf to shuffle the file lines common/rc | 7 +++++++ tests/btrfs/004 | 2 +- tests/btrfs/179 | 4 ++-- tests/btrfs/192 | 14 ++++---------- 4 files changed, 14 insertions(+), 13 deletions(-) -- 2.41.0