diff --git a/profile.d/processes.sh b/profile.d/processes.sh
index b474f9b..ee1ebf5 100644
--- a/profile.d/processes.sh
+++ b/profile.d/processes.sh
@@ -1,6 +1,6 @@
 #!/usr/bin/env bash
 # ------------------------------------------------------------------------------
-# Copyright (c) 2013-2026 Geoffray Levasseur <fatalerrors@geoffray-levasseur.org>
+# Copyright (c) 2013-2022 Geoffray Levasseur <fatalerrors@geoffray-levasseur.org>
 # Protected by the BSD3 license. Please read bellow for details.
 #
 # * Redistribution and use in source and binary forms,
@@ -128,12 +128,12 @@ gpid()
     for pid in $@; do
         local result=$(ps $psopt | grep $pid | awk '{print $1}' | sed "s/\n/ /")
         if [[ $single ]]; then
-            [[ $result ]] && echo "${result//$'\n'/ }"
+            [[ -n "$result" ]] && echo "${result//$'\n'/ }"
         else
-            [[ $result ]] && echo "$pid: ${result//$'\n'/ }"
+            [[ -n "$result" ]] && echo "$pid: ${result//$'\n'/ }"
         fi
     done
-    [[ $result ]] || return 1
+    [[ -n "$result" ]] || return 1
 }
 export -f gpid
 # ------------------------------------------------------------------------------
@@ -155,8 +155,14 @@ ku()
         disp E "Usage: ku <username1 [username2 ...]>"
         return 1
     fi
-    for u in $@; do
-        killall -u "$u"
+    local users="$@"
+    for u in $users; do
+        if ! id "$u" >/dev/null 2>&1; then
+            disp E "User '$u' does not exist."
+            return 1
+        else
+            killall -u "$u"
+        fi
     done
 }
 export -f ku
@@ -187,7 +193,7 @@ kt()
         return 1
     fi
 
-    children_pids=$(pgrep -P "$parent_pid")
+    local children_pids=$(pgrep -P "$parent_pid")
 
     for pid in $children_pids; do
         kt "$pid" "$@" || break
@@ -198,3 +204,4 @@ kt()
 
 
 # EOF
+