Linux Commands Cheat Sheet

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常用命令

code

• -n -新建窗口
• -r -使用已打开的窗口打开文件

grep

• -i - 忽略大小写
• -w 只显示全字符合的列。
• -x 只显示全列符合的列。
• -E 使用正则表达式
• 重定向 > 是覆盖模式，>> 是追加模式
• grep [options] PATTERN [FILE…]
• tail -f file
• less -N file
• htop
• scp

vim

• :set number 在编辑文件时显示行号

SYSTEM INFORMATION

• uname -a - Display Linux system information
• uname -r - Display kernel release information
• cat /etc/redhat-release - Show which version of redhat installed
• cat /etc/issue - 查看 Linux 系统版本信息
• uptime - Show how long the system has been running + load
• hostname - Show system host name
• hostname -I - Display the IP addresses of the host
• last reboot - Show system reboot history
• date - Show the current date and time
• cal - Show this month’s calendar
• w - Display who is online
• whoami - Who you are logged in as

HARDWARE INFORMATION

• dmesg - Display messages in kernel ring buffer
• cat /proc/cpuinfo - Display CPU information
• cat /proc/meminfo - Display memory information
• free -h - Display free and used memory ( -h for human readable, -m for MB, -g for GB.)
• lspci -tv - Display PCI devices
• lsusb -tv - Display USB devices
• dmidecode - Display DMI/SMBIOS (hardware info) from the BIOS
• hdparm -i /dev/sda - Show info about disk sda
• hdparm -tT /dev/sda - Perform a read speed test on disk sda
• badblocks -s /dev/sda - Test for unreadable blocks on disk sda

PERFORMANCE MONITORING AND STATISTICS

• top - Display and manage the top processes
• htop - Interactive process viewer (top alternative)
• mpstat 1 - Display processor related statistics
• vmstat 1 - Display virtual memory statistics
• iostat 1 - Display I/O statistics
• tail 100 /var/log/messages - Display the last 100 syslog messages (Use /var/log/syslog for Debian based systems.)
• tcpdump -i eth0 - Capture and display all packets on interface eth0
• tcpdump -i eth0 'port 80' - Monitor all traffic on port 80 ( HTTP )
• lsof - List all open files on the system
• lsof -u user - List files opened by user
• free -h - Display free and used memory ( -h for human readable, -m for MB, -g for GB.)
• watch df -h - Execute “df -h”, showing periodic update

USER INFORMATION AND MANAGEMENT

• id - Display the user and group ids of your current user.
• last - Display the last users who have logged onto the system.
• who - Show who is logged into the system.
• w - Show who is logged in and what they are doing.
• groupadd test - Create a group named “test”.
• useradd -c "John Smith" -m john - Create an account named john, with a comment of “John Smith” and create the user’s home directory.
• userdel john - Delete the john account.
• usermod -aG sales john - Add the john account to the sales group

FILE AND DIRECTORY COMMANDS

• ls -al - List all files in a long listing (detailed) format
• pwd - Display the present working directory
• mkdir directory - Create a directory
• rm file - Remove (delete) file
• rm -r directory - Remove the directory and its contents recursively
• rm -f file - Force removal of file without prompting for confirmation
• rm -rf directory - Forcefully remove directory recursively
• cp file1 file2 - Copy file1 to file2
• cp -r source_directory destination - Copy source_directory recursively to destination. If destination exists, copy source_directory into destination, otherwise create destination with the contents of source_directory
• mv file1 file2 - Rename or move file1 to file2. If file2 is an existing directory, move file1 into directory file2
• ln -s /path/to/file linkname - Create symbolic link to linkname
• touch file - Create an empty file or update the access and modification times of file.
• cat file - View the contents of file
• less file - Browse through a text file
• head file - Display the first 10 lines of file
• tail file - Display the last 10 lines of file
• tail -f file - Display the last 10 lines of file and “follow” the file as it grows.

PROCESS MANAGEMENT

• ps - Display your currently running processes
• ps -ef - Display all the currently running processes on the system.
• ps -ef | grep processname - Display process information for processname
• top - Display and manage the top processes
• htop - Interactive process viewer (top alternative)
• kill pid - Kill process with process ID of pid
• killall processname - Kill all processes named processname
• program & - Start program in the background
• bg - Display stopped or background jobs
• fg - Brings the most recent background job to foreground
• fg n - Brings job n to the foreground

NETWORKING

• ifconfig -a - Display all network interfaces and ip address
• ifconfig eth0 - Display eth0 address and details
• ethtool eth0 - Query or control network driver and hardware settings
• ping host - Send ICMP echo request to host
• whois domain - Display whois information for domain
• dig domain - Display DNS information for domain
• dig -x IP_ADDRESS - Reverse lookup of IP_ADDRESS
• host domain - Display DNS ip address for domain
• hostname -i - Display the network address of the host name.
• hostname -I - Display all local ip addresses
• wget http://domain.com/file - Download http://domain.com/file
• netstat -nutlp - Display listening tcp and udp ports and corresponding programs

ARCHIVES (TAR FILES)

• tar cf archive.tar directory - Create tar named archive.tar containing directory.
• tar xf archive.tar - Extract the contents from archive.tar.
• tar czf archive.tar.gz directory - Create a gzip compressed tar file name archive.tar.gz.
• tar xzf archive.tar.gz - Extract a gzip compressed tar file.
• tar cjf archive.tar.bz2 directory - Create a tar file with bzip2 compression
• tar xjf archive.tar.bz2 - Extract a bzip2 compressed tar file.

INSTALLING PACKAGES

• yum search keyword - Search for a package by keyword.

• yum install package - Install package.

• yum info package - Display description and summary information about package.

• rpm -i package.rpm - Install package from local file named package.rpm

• yum remove package - Remove/uninstall package.

• Install software from source code.

  tar zxvf sourcecode.tar.gz
  cd sourcecode
  ./configure
  make
  make install

SEARCH

• grep pattern file - Search for pattern in file
• grep -r pattern directory - Search recursively for pattern in directory
• locate name - Find files and directories by name
• find /home/john -name 'prefix*' - Find files in /home/john that start with “prefix”.
• find /home -size +100M - Find files larger than 100MB in /home

SSH LOGINS

• ssh host - Connect to host as your local username.
• ssh user@host - Connect to host as user
• ssh -p port user@host - Connect to host using port

FILE TRANSFERS

• scp file.txt server:/tmp Secure copy file.txt to the /tmp folder on server
• scp server:/var/www/*.html /tmp Copy *.html files from server to the local /tmp folder.
• scp -r server:/var/www /tmp Copy all files and directories recursively from server to the current system’s /tmp folder.
• rsync -a /home /backups/ Synchronize /home to /backups/home
• rsync -avz /home server:/backups/ Synchronize files/directories between the local and remote system with compression enabled

DISK USAGE

• df -h - Show free and used space on mounted filesystems
• df -i - Show free and used inodes on mounted filesystems
• fdisk -l - Display disks partitions sizes and types
• du -ah - Display disk usage for all files and directories in human readable format
• du -sh - Display total disk usage off the current directory

DIRECTORY NAVIGATION

• To go up one level of the directory tree. (Change into the parent directory.)
• Go to the $HOME directory
• Change to the /etc directory