apt-get install libpam-unix2
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http://www.linux-pam.org/Linux-PAM-html/adg-example.html
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https://gist.github.com/jamshid/d03bb69f6a9076b178d73e69ee5446c4
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pam_exception_authenticate
org.jvnet.libpam.PAMException: pam_authenticate failed : Authentication failure
        at org.jvnet.libpam.PAM.check(PAM.java:106)
        at org.jvnet.libpam.PAM.authenticate(PAM.java:124)
        at com.sun.enterprise.security.ee.auth.login.PamLoginModule.authenticate(PamLoginModule.java:114)
        at com.sun.enterprise.security.ee.auth.login.PamLoginModule.authenticateUser(PamLoginModule.java:65)
        at com.sun.enterprise.security.BasePasswordLoginModule.login(BasePasswordLoginModule.java:145)