The shell used to run the tests is generally /bin/sh, which does not support process substitution. Fixes: b990df0bef9e (tests/util/grub-fs-tester: Fix EROFS label tests in grub-fs-tester) Signed-off-by: Glenn Washburn <development@efficientek.com> Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com> Reviewed-by: Sudhakar Kuppusamy <sudhakar@linux.ibm.com>