Summary of common View system Information and log commands in CentOS system

system log files ( can be viewed by cat or Tail command )

/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 Information

# 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