diff --git a/util.go b/proc.go
similarity index 71%
rename from util.go
rename to proc.go
index 1831dd9..f1e8ca7 100644
--- a/util.go
+++ b/proc.go
@@ -1,7 +1,8 @@
+//go:build darwin || dragonfly || freebsd || linux || netbsd || openbsd
+
 package main
 
 import (
-	"io/ioutil"
 	"os"
 	"strconv"
 	"strings"
@@ -10,7 +11,7 @@ import (
 func GetProcessPIDs(name string) ([]int, error) {
 	var pids []int
 
-	dir, err := ioutil.ReadDir("/proc/")
+	dir, err := os.ReadDir("/proc/")
 	if err != nil {
 		return nil, err
 	}
@@ -23,7 +24,10 @@ func GetProcessPIDs(name string) ([]int, error) {
 			}
 
 			if strings.Contains(string(cmdline), name) {
-				pid, _ := strconv.Atoi(entry.Name())
+				pid, err := strconv.Atoi(entry.Name())
+				if err != nil {
+					continue
+				}
 				pids = append(pids, pid)
 			}
 		}