title: How to find host string?
body: <p>I have just installed Oracle - DevSuitehome2, Oracle Database 10g Express Edition and Oracle Developer Suit - DevSuiteHome2. 
  I am new to this Oracle forms, Oracle Reports, etc. During installation, it asked for the password. I entered it. It was written that use your password in SYS and SYSTEM Database accounts. After installation was completed I started SQL *Plus. I entered SYSTEM as username and my password. </p>
  
  <pre><code>                 ERROR:
                   ORA-12154 :TNS:could not resolve the connect identifier specified
  </code></pre>
  
  <p>I also tried SYS as my username but still same error. I opened cmd and typed: </p>
  
  <pre><code>                 C:\&gt;sqlplus /nolog
                   SQL&gt; conn / as sysdba
                   connected.
                   SQL&gt; desc dba_users
                   NAME           NULL?           TYPE
                   ------         ------          --------
                   USERNAME                       VARCHAR2(30)
                   USERID                         NUMBER
                   PASSWORD                       VARCHAR2(30)
                   . 
                   .
  
                   SQL&gt;select username,password from user_dba;
                   USERNAME                    PASSWORD
                   -----------                 -------------
                   SYS                         XXXXXXXXXX
                   SYSTEM                      XXXXXXXXXX
                   SCOTT                       XXXXXXXXXX
                   HR                          XXXXXXXXXX
                   . 
                   .  
  </code></pre>
  
  <p>All passwords were written in complex form so to simplify it I thought to change any one of the password. So, I wrote :</p>
  
  <pre><code>                SQL&gt; alter user HR identified by password;
                  user altered.
  </code></pre>
  
  <p>Then I tried to use these while opening SQL *Plus. It did not work. I don't know what's the host string now. Can I get the complete information about users, passwords and host string ? I tried to search for tnsnames.ora file too but could not find out. All files, folders are all mess.</p>