Common view Log commands in CentOS systems __centos

Linux IDE RedHat firewall activity.
Cat
Tail-f

Log file description
/var/log/message information and error logs after system startup is one of the most common logs in red Hat Linux
/var/log/secure Security-related log information
/var/log/maillog Mail-related log information
/var/log/cron log information related to timed tasks
/var/log/spooler log information related to UUCP and news devices
The/var/log/boot.log daemon starts and stops related log messages

System:
# uname-a # View kernel/operating system/CPU information
# cat/etc/issue
# cat/etc/redhat-release # View operating system version
# cat/proc/cpuinfo # View CPU Information
# hostname # View computer name
# LSPCI-TV # list all PCI devices
# LSUSB-TV # list all USB devices
# lsmod # list the loaded kernel modules
# env # View Environment variables
Resources:
# free-m # View memory usage and swap area usage
# df-h # View the usage of each partition
# du-sh < directory name > # View the size of the specified directory
# grep Memtotal/proc/meminfo # View Total Memory
# grep Memfree/proc/meminfo # View Idle memory
# uptime # View system run time, number of users, load
# cat/proc/loadavg # View System load
Disks and partitions:
# Mount | COLUMN-T # View the partition status of the hook
# fdisk-l # View all partitions
# swapon-s # View all swap partitions
# hdparm-i/dev/hda # View disk parameters (IDE devices only)
# DMESG | grep IDE # View IDE Device detection status at startup
Internet:
# ifconfig # View properties of all network interfaces
# iptables-l # View firewall settings
# route-n # View the routing table
# netstat-lntp # View all listening ports
# netstat-antp # View all connections that have been established
# netstat-s # View Network statistics
Process:
# ps-ef # View All Processes
# top # Displays the status of the process in real time (another article contains a detailed description)
User:
# w # View active Users
# ID < user name > # view specified user information
# last # View User login log
# cut-d:-f1/etc/passwd # View All users of the system
# cut-d:-f1/etc/group # View all groups of the system
# crontab-l # View scheduled tasks for the current user
Service:
# chkconfig–list # List all system services
# Chkconfig–list | grep on # Lists all initiated system services
Program:
# rpm-qa # View all installed Packages