I'm using busybox with a limited passwd (I don't have --stdin option) and without
chpasswd and I need to change the password of an user from bash. Here is my best result:
echo newpassword > pwdfile echo newpassword > pwdfile cat pwdfile | passwd myuser Changing password for myuser Enter the new password (minimum of 5, maximum of 8 characters) Please use a combination of upper and lower case letters and numbers. Enter new password: Bad password: too simple. Warning: weak password (continuing). Re-enter new password: passwd: The password for myuser is unchanged.