commands for viewing logs under Linux systems

Log file description

/var/log/message information and error logs after system startup is one of the most commonly used 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

scheduled Tasks

/var/log/spooler log information related to UUCP and news devices

/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 OS 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 loaded kernel modules

# env # View environment variables

Resources

# free-m # View memory usage and swap area usage

# df-h # View each partition usage

# du-sh < directory name > # View the size of the specified directory

# grep Memtotal/proc/meminfo # View Total Memory

# grep Memfree/proc/meminfo # View the amount of free Ram

# uptime # View system run time, number of users, load

# cat/proc/loadavg # View System load

Disks and partitions

# Mount | Column-t # View attached partition status

# fdisk-l # View all Partitions

# swapon-s # View all swap partitions

# hdparm-i/dev/hda # View disk parameters (for IDE devices only)

# DMESG | grep IDE # View IDE Device detection status at startup

Internet

# ifconfig # View the properties of all network Interfaces #

Iptables-l # View firewall Settings

# route-n # View routing Table

# netstat-lntp # View all listening ports

# netstat- ANTP # View all established Connections

# netstat-s # View Network statistics

Process

# ps-ef # View All Processes

# top # Real-time display of process status (another article with a detailed description)

User

# w # view active user

# ID < username > # 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 # Lists all system Services

# Chkconfig list | grep on # List all initiated system services

Program

# rpm-qa # View all installed Packages