Few Linux TIPS

How to verify any change in files by RPM

#rpm -Va | less
==> very helpful to check every file on your computer,you will now which files are modified
say
.......T c /etc/inittab
..5....T c /etc/pki/nssdb/secmod.db
.......T c /etc/audit/auditd.conf
....L... c /etc/pam.d/system-auth
S.5....T c /etc/sysconfig/system-config-securitylevel
.......T c /etc/mail/sendmail.cf
S.5....T c /var/log/mail/statistics
.M...... c /etc/cups/classes.conf

where==>
S file Size differs
M Mode differs (includes permissions and file type)
5 MD5 sum differs
L readLink path mis-match
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Netstat

very nice utility to know what is running on your system

#netstat -atu
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PS

Check the processes

#ps -aux

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Last

who logged into the system in Past

#last -a