W: GPG error: stable Release: The following signatures couldn’t be verified because the public key is not available: NO_PUBKEY E585066A30C18A2B

W: GPG error: http://dl.google.com stable Release: The following signatures couldn’t be verified because the public key is not available: NO_PUBKEY A040830F7FAC5991
W: GPG error: http://deb.opera.com stable Release: The following signatures couldn’t be verified because the public key is not available: NO_PUBKEY E585066A30C18A2B
W: GPG error: http://ppa.launchpad.net precise Release: The following signatures couldn’t be verified because the public key is not available: NO_PUBKEY 52A794126E3AB2D3
W: GPG error: http://ppa.launchpad.net precise Release: The following signatures couldn’t be verified because the public key is not available: NO_PUBKEY 83FBA1751378B444
W: GPG error: http://ppa.launchpad.net precise Release: The following signatures couldn’t be verified because the public key is not available: NO_PUBKEY 00A6F0A3C300EE8C
W: GPG error: http://ppa.launchpad.net precise Release: The following signatures couldn’t be verified because the public key is not available: NO_PUBKEY 531EE72F4C9D234C
W: GPG error: http://ppa.launchpad.net precise Release: The following signatures couldn’t be verified because the public key is not available: NO_PUBKEY 7FB8BEE0A1F196A8
W: GPG error: http://ppa.launchpad.net precise Release: The following signatures couldn’t be verified because the public key is not available: NO_PUBKEY A7E13D78E4A4F4F4
W: GPG error: http://ppa.launchpad.net precise Release: The following signatures couldn’t be verified because the public key is not available: NO_PUBKEY 464AD83D4631BBEA
W: GPG error: http://download.virtualbox.org precise InRelease: The following signatures couldn’t be verified because the public key is not available: NO_PUBKEY 54422A4B98AB5139
W: GPG error: http://ppa.launchpad.net precise Release: The following signatures couldn’t be verified because the public key is not available: NO_PUBKEY 6AF0E1940624A220
W: GPG error: http://ppa.launchpad.net precise Release: The following signatures couldn’t be verified because the public key is not available: NO_PUBKEY 991E6CF92D9A3C5B
W: GPG error: http://ppa.launchpad.net precise Release: The following signatures couldn’t be verified because the public key is not available: NO_PUBKEY C2518248EEA14886
W: GPG error: http://ppa.launchpad.net precise Release: The following signatures couldn’t be verified because the public key is not available: NO_PUBKEY C2518248EEA14886
W: GPG error: http://ppa.launchpad.net precise Release: The following signatures couldn’t be verified because the public key is not available: NO_PUBKEY C2518248EEA14886
W: GPG error: http://mirrors.dotsrc.org precise-getdeb Release: The following signatures couldn’t be verified because the public key is not available: NO_PUBKEY A8A515F046D7E7CF
W: GPG error: http://linux.dropbox.com precise Release: The following signatures couldn’t be verified because the public key is not available: NO_PUBKEY FC918B335044912E
W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/precise/Release Unable to find expected entry ‘estricted/binary-i386/Packages’ in Release file (Wrong sources.list entry or malformed file)

here is the solution:

apt-key adv –keyserver keyserver.ubuntu.com –recv-keys A040830F7FAC5991 A8A515F046D7E7CF E585066A30C18A2B 52A794126E3AB2D3 83FBA1751378B444 00A6F0A3C300EE8C  531EE72F4C9D234C 7FB8BEE0A1F196A8  A7E13D78E4A4F4F4  464AD83D4631BBEA  6AF0E1940624A220  991E6CF92D9A3C5B C2518248EEA14886  C2518248EEA14886  C2518248EEA14886 54422A4B98AB5139 FC918B335044912E

 

 

 

check linux configuration files syntax for errors

OpenSSH/usr/sbin/sshd -t && echo $?
/usr/sbin/sshd -T
Apache/usr/sbin/apache2 -t
apachectl configtest
nginx/usr/local/nginx/sbin/nginx -t
/usr/local/nginx/sbin/nginx -t -c /usr/local/nginx/conf/nginx.conf
lighttpd/usr/local/sbin/lighttpd -t -f /usr/local/etc/lighttpd/cyberciti.biz/lighttpd.conf
Bind (named server config)named-checkconf /etc/named.conf
Bind (zone syntx)named-checkzone cyberciti.biz /var/named/zone.cyberciti.biz
Squid proxy/usr/sbin/squid -k check
/usr/sbin/squid -k parse
MySQL servermysqld –verbose –help
/usr/libexec/mysqld –verbose –help 1>/dev/null
Postfix MTApostfix check
postfix -vvv
Samba SMB/CIFStestparm -v
tcpdtcpdchk
tcpdchk -v
dhcpd (DHCP / BOOTP) serverdhcpd -t -cf /path/to/dhcpd.testing.conf
vsftpd servervsftpd -olisten=NO /path/to/vsftpd.testing.conf
nagiosnagios -v /path/to/testing/nagios.cfg
Openntpd NTPD serverntpd -d -f /usr/local/etc/ntpd.conf -n
Xorg (X11 Server)Xorg -config /path/to/xorg.conf.new -retro
syslogd / rsyslogdrsyslogd -c4 -f /etc/rsyslog.testing.conf -N 1
CUPS Printing Systemcupsd -f -c /path/to/cupsd.testing.conf -t
slapd (OpenLDAP)slapd -Tt
varnishdvarnishd -C -f /path/to/wordpress.vlc
exim MTAexim -bV
Bash/Ksh scriptsbash -n ./myscript
ksh -n /path/to/script.ksh
BSD pf firewallpfctl -nf /etc/pf.conf
proftpdproftpd -t -c /path/to/proftpd.testing.conf
Perl scriptsperl -c /path/to/script.pl
perl -wc /path/to/script.pl

http://www.cyberciti.biz/tips/check-unix-linux-configuration-file-for-syntax-errors.html