The password length

Edit the passwd file (vi /etc/pam.d/passwd) and remove the following line:
password required /lib/security/pam_stack.so service=system-auth

Edit the system-auth file (vi /etc/pam.d/system-auth) and remove the lines:
password required /lib/security/pam_cracklib.so retry=3
password sufficient /lib/security/pam_unix.so nullok use_authtok md5 shadow
password required /lib/security/pam_deny.so

Now add the following lines to /etc/pam.d/passwd. We use the PAM “pam_cracklib�? module here with the argument “minlen�? to enforce the password length.
password required /lib/security/pam_cracklib.so retry=3 minlen=12
password sufficient /lib/security/pam_unix.so nullok use_authtok md5 shadow
password required /lib/security/pam_deny.so