diff --git a/T/T b/T/T
index f221923..71456ce 100755
--- a/T/T
+++ b/T/T
@@ -120,6 +120,7 @@ B<tee>(1), B<cat>(1)
 =cut
 
 find_tmp_dir() {
+    # Search for .tmp in all parent dirs
     dir="$1"
     if [ -d "$1"/.tmp ] ; then
 	echo "$1"/.tmp
@@ -134,73 +135,68 @@ find_tmp_dir() {
     fi
 }
 
-tmpdir="$(find_tmp_dir .)"
+oldversion() {
+    # Find $oldversion of $name
+    local tmpdir="$1"
+    local name="$2"
+    local oldversion="$3"
+    find "$tmpdir" -name "$name"-'[0-9][0-9][0-9][0-9]-[0-9][0-9]-[0-9][0-9]?[0-9][0-9]:[0-9][0-9]:[0-9][0-9]-[0-9]*' |
+	sort |
+	tail -n $oldversion |
+	head -n 1
+}
+
+#debug_log=/tmp/T-debug
+debug_log=/dev/null
+
+tmpdir=$(find_tmp_dir .)
 mkdir -p "$tmpdir"
 
-T_DIR="$tmpdir"
+case "$1" in
+    (-[0-9]*) oldversion=${1:1}
+	      shift
+	      ;;
+esac
 
-#DEBUG_LOG=/tmp/T-debug
-DEBUG_LOG=/dev/null
-
-if echo $1 | egrep '^-[0-9]+$' >/dev/null; then
-  T_BACK_NO=$(echo $1 | sed -e 's:-::')
-  shift
-  if [ -z "$1" ]; then
-    # No filename given. Default = tempfile
-    T_NO_SLASH=tempfile
-  else
-    # Map / to __ to avoid creating dirs in ~/.tmp
-    T_NO_SLASH=$(echo $1 | sed -e 's:/:__:g')
-  fi
-  T_TEMPFIL=$T_DIR/$T_NO_SLASH
-  T_BACK_FILENAME=$(find $T_DIR -name "$T_NO_SLASH"-'[0-9][0-9][0-9][0-9]-[0-9][0-9]-[0-9][0-9]?[0-9][0-9]:[0-9][0-9]:[0-9][0-9]-[0-9]*' \
-  | sort | tail -n $T_BACK_NO | head -n 1)
-  if [ -z "$T_BACK_FILENAME" ]; then
-    T_TEMPFIL=$T_DIR/$T_NO_SLASH
-  else
-    T_TEMPFIL=$T_BACK_FILENAME
-  fi
+if [ -z "$1" ]; then
+    name=tempfile
 else
-  if [ -z "$1" ]; then
-    # No filename given. Default = tempfile
-    T_TEMPFIL=$T_DIR/tempfile
-  else
-    # Map / to __ to avoid creating dirs in ~/.tmp
-    T_NO_SLASH=$(echo $1 | sed -e 's:/:__:g')
-    T_TEMPFIL=$T_DIR/$T_NO_SLASH
-  fi
+    name=$(echo "$1" | sed -e 's:/:__:g')
 fi
 
+if [ -z "$oldversion" ]; then
+    readpathname="$tmpdir/$name"
+    writename="$name"-`date +"%Y-%m-%dT%H:%M:%S"`-$$
+    writepathname="$tmpdir/$writename"
+else
+    readpathname=$(oldversion "$tmpdir" "$name" "$oldversion")
+    writepathname="$readpathname"
+fi
 
-T_NY_FIL="$T_TEMPFIL"-`date +"%Y-%m-%dT%H:%M:%S"`-$$
-
-mkdir $T_DIR 2>/dev/null
+echo "$tmpdir $pathname $name $oldversion" >> $debug_log
 
 if tty -s ; then
-  # STDIN is terminal
-  # Don't care what STDOUT is
-  # T | cat         => T= cat file
-  # T               => T= cat file
-  echo cat "$T_TEMPFIL" >> $DEBUG_LOG
-  cat "$T_TEMPFIL"
+    # STDIN is terminal
+    # Don't care what STDOUT is
+    # T | cat         => T= cat file
+    # T               => T= cat file
+    echo cat "$readpathname" >> $debug_log
+    cat "$readpathname"
 else
-  # STDIN redir'ed
-
-  if [ -t 1 ] ; then
-    # STDOUT = terminal
-    # cat | T       => T= >file
-    echo cat '>' "$T_NY_FIL" >> $DEBUG_LOG
-    cat > "$T_NY_FIL"
-  else
-    # STDOUT redir'ed
-    # cat | T | cat => T= tee file
-    echo tee "$T_NY_FIL" >> $DEBUG_LOG
-    tee "$T_NY_FIL"
-  fi
-
-  # Remove hardlink to most recent file
-  rm "$T_TEMPFIL" 2> /dev/null
-
-  # make a hardlink to the most recent file
-  ln "$T_NY_FIL" "$T_TEMPFIL"
+    if [ -t 1 ] ; then
+	# STDOUT = terminal
+	# cat | T       => T= >file
+	echo cat '>' "$writepathname" >> $debug_log
+	cat > "$writepathname"
+    else
+	# STDOUT redir'ed
+	# cat | T | cat => T= tee file
+	echo tee "$writepathname" >> $debug_log
+	tee "$writepathname"
+    fi
+    if [ -z "$oldversion" ]; then
+	echo ln -s "$writename" "$readpathname" >> $debug_log
+	# Replace symlink to most recent file
+	ln -fs "$writename" "$readpathname"
+    fi
 fi
diff --git a/plotpipe/README b/plotpipe/README
index 7bdac30..9fb3c2b 100644
--- a/plotpipe/README
+++ b/plotpipe/README
@@ -26,11 +26,11 @@ column, the line number is treated as the x-axis.
 Examples:
 
     seq 1 100 | plotpipe
-    seq 1 100 | shuf | plotpipe
+    seq 1 100 | shuf | plotpipe --smooth 10 --log y
     paste <(seq 1 100) <(seq 1 100) <(seq 1 100 | shuf) | plotpipe
     (echo "#Title"; echo "#Subtitle";
-     printf "Column1\tColumn2\tColumn3";
-     paste <(seq 1 100) <(seq 1 100) <(seq 1 100 | shuf) ) | plotpipe
+     printf "Column 1\tColumn 2\tColumn 3\n";
+     paste <(seq 1 100) <(seq 51 150) <(seq 1 100 | shuf) ) | plotpipe
 
 Copyright (C) 2020-2021 Ole Tange, http://ole.tange.dk and Free
 Software Foundation, Inc.