Cat
Tail-f
Japanese text description
/Var/log/message information and error logs after the system is started. It is one of the most common logs in Red Hat Linux.
/Var/log/secure security-related log information
/Var/log/maillog and mail-related log information
/Var/log/cron log information related to scheduled tasks
/Var/log/spooler logs related to UCP 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 the operating system version
# Cat/proc/cpuinfo # view CPU Information
# Hostname # view the computer name
# Lspci-TV # list all PCI devices
# Lsusb-TV # list all USB devices
# Lsmod # list loaded Kernel Modules
# Env # view environment variables
Resource:
# Free-m # view memory usage and swap zone usage
# Df-h # view the usage of each partition
# Du-sh <Directory Name> # view the size of a specified directory
# Grep MemTotal/proc/meminfo # view total memory
# Grep MemFree/proc/meminfo # view the Amount of idle memory
# Uptime # view system running time, number of users, and load
# Cat/proc/loadavg # view system load
Disks and partitions:
# Mount | column-t # view the status of the mounted Partition
# Fdisk-l # view all partitions
# Swapon-s # view all swap partitions
# Hdparm-I/dev/hda # view disk parameters (only applicable to IDE devices)
# Dmesg | grep IDE # view the IDE Device Detection Status at startup
Network:
# Ifconfig # view the attributes of all network interfaces
# Iptables-L # view firewall settings
# Route-n # view the route 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 # display Process status in real time (for details in another article)
User:
# W # view active users
# Id <User Name> # view specified user information
# Last # view User Logon logs
# Cut-d:-f1/etc/passwd # view all users in the system
# Cut-d:-f1/etc/group # view all groups in the system
# Crontab-l # view the scheduled tasks of the current user
Service:
# Chkconfig-list # list all system services
# Chkconfig-list | grep on # list all started system services
Program:
# Rpm-qa # view all installed software packages