How to edit /etc/pam.d/sytem-auth-ac file in linux?
<p>I tried several times to edit this file but after several items it always show up the old default files script.
I need to replace lines or edit this file for making a User management Policy.</p>

<p>Commands I used in my script:</p>

<pre><code># sed '14 i \password    requisite     pam_cracklib.so try_first_pass retry=3 minlen=8 lcredit=-1 dcredit=1 difok=4 maxrepeat=2 ocredit=1 ucredit=1 /etc/pam.d/system-auth-ac

#sed '15 i \password    sufficient    pam_unix.so shadow  try_first_pass use_authtok remember=6 /etc/pam.d/system-auth-ac


#sed '4 i \auth        required      pam_tally2.so onerr=fail file=/var/log/faillog deny=6 unlock_time=3600'  /etc/pam.d/system-auth-ac

#sed '10 i \account     required      pam_tally2.so file=/var/log/faillog' /etc/pam.d/system-auth-ac

#sed '13 i \account     sufficient    pam_localuser.so' /etc/pam.d/system-auth-ac
</code></pre>

<p>Above are the commands which i write to add this in my script if anyone has some good suggestion plz put in comments. 
Help will really be appreciated.</p>