diff --git a/entrypoint b/entrypoint
index d3a528f..e5f2601 100755
--- a/entrypoint
+++ b/entrypoint
@@ -51,7 +51,7 @@ function createUser() {
     gid="${args[$[$index+3]]}"; validateArg "GID" "$gid" "$reGid" || return 1
     dir="${args[$[$index+4]]}"; validateArg "dirs" "$dir" "$reDir" || return 1
 
-    if $(cat /etc/passwd | cut -d: -f1 | grep -q "^$user:"); then
+    if getent passwd $user > /dev/null; then
         log "WARNING: User \"$user\" already exists. Skipping."
         return 0
     fi
@@ -63,7 +63,7 @@ function createUser() {
     fi
 
     if [ -n "$gid" ]; then
-        if ! $(cat /etc/group | cut -d: -f3 | grep -q "$gid"); then
+        if ! getent group $gid > /dev/null; then
             groupadd --gid $gid "group_$gid"
         fi
 
@@ -77,7 +77,7 @@ function createUser() {
 
     # Retrieving user id to use it in chown commands instead of the user name
     # to avoid problems on alpine when the user name contains a '.'
-    uid=`id $user -u`
+    uid="$(id -u $user)"
 
     if [ -n "$pass" ]; then
         echo "$user:$pass" | chpasswd $chpasswdOptions