hardlink: (man) add note note about ULFILEEQ_DEBUG=

Addresses: https://github.com/util-linux/util-linux/discussions/3323
Signed-off-by: Karel Zak <kzak@redhat.com>

diff --git a/misc-utils/hardlink.1.adoc b/misc-utils/hardlink.1.adoc
index 29d6dca3e6cca23c9fbabf922f9de28b7e64969a..21b976297e0d0bc6abc65c1781b835d23745f280 100644 (file)
--- a/misc-utils/hardlink.1.adoc
+++ b/misc-utils/hardlink.1.adoc
@@ -153,6 +153,11 @@ include::man-common/help-version.adoc[]
 
 *hardlink* takes one or more directories which will be searched for files to be linked.
 
+== ENVIRONMENT
+
+*ULFILEEQ_DEBUG*=all::
+Enables debug output for file comparisons.
+
 == BUGS
 
 The original *hardlink* implementation uses the option *-f* to force hardlinks creation between filesystem. This very rarely usable feature is no more supported by the current *hardlink*.