diff --git a/README.md b/README.md
index 247ebde..68ecd32 100644
--- a/README.md
+++ b/README.md
@@ -5,3 +5,4 @@ A simple rc script to kickstart your system.
 ## depends
 
 * Enabled sysrq or halt from suckless.org's ubase.
+* /proc support.
diff --git a/tools/killall5.in b/tools/killall5.in
index f896b83..e13f9fe 100644
--- a/tools/killall5.in
+++ b/tools/killall5.in
@@ -39,7 +39,7 @@ get_procs_to_kill() {
 
 pids_exist() {
 	for i in "$@"; do
-		if kill -0 "$i" 2>/dev/null; then
+		if [[ -d "/proc/$i" ]]; then
 			return 0
 		fi
 	done