Added the ENVIRONMENT section.

docs/pv.1

@@ -1,4 +1,4 @@
-.TH PV 1 "March 2024" Linux "User Manuals"
+.TH PV 1 "April 2024" Linux "User Manuals"
 .SH NAME
 pv \- monitor the progress of data through a pipe
 .SH SYNOPSIS
@@ -663,6 +663,40 @@ Memory allocation failed.
 A zero exit status indicates no problems.
 
 
+.SH ENVIRONMENT
+The following environment variables may affect
+.BR pv :
+
+.TP
+.B HOME
+The current user's home directory.  This may be used by the remote control
+mechanism
+(the
+.B \-\-remote
+option)
+to exchange messages between
+.B pv
+instances: if the
+.I /run/user/UID/
+directory does not exist (where
+.I UID
+is the current user ID), then
+.I $HOME/.pv/
+will be used instead.
+.TP
+.BR TMPDIR ", " TMP
+The directory to create per-tty lock files for the terminal when using the
+.B \-\-cursor
+option.  If
+.B TMPDIR
+is set to a non-empty value, it is the directory under which lock files are
+created.  Otherwise, if
+.B TMP
+is set, then it is used; and if neither are set, then
+.I /tmp
+is used.
+
+
 .SH AUTHOR
 Written by Andrew Wood, with patches submitted by various other people. 
 Please see the package's ACKNOWLEDGEMENTS file for a complete list of

docs/pv.1.md

@@ -504,6 +504,26 @@ Any other exit status is a bitmask of the following:
 
 A zero exit status indicates no problems.
 
+# ENVIRONMENT
+
+The following environment variables may affect **pv**:
+
+**HOME**
+
+:   The current user\'s home directory. This may be used by the remote
+    control mechanism (the **\--remote** option) to exchange messages
+    between **pv** instances: if the */run/user/UID/* directory does not
+    exist (where *UID* is the current user ID), then *\$HOME/.pv/* will
+    be used instead.
+
+**TMPDIR**, **TMP**
+
+:   The directory to create per-tty lock files for the terminal when
+    using the **\--cursor** option. If **TMPDIR** is set to a non-empty
+    value, it is the directory under which lock files are created.
+    Otherwise, if **TMP** is set, then it is used; and if neither are
+    set, then */tmp* is used.
+
 # AUTHOR
 
 Written by Andrew Wood, with patches submitted by various other people.