Linux Basic Commands

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4 years ago

Linux Basic Commands

List of most commonly used common used by Development, Testing, and System Administrator engineers in Linux Environment.

SYSTEM
- - uname -a : Display linux system information
  - uname -r : Display kernel release information
  - uptime : Show how long the system has been running + load
  - hostname : Show system host name
  - hostname -i : Display the IP address of the host
  - last reboot : Show system reboot history
  - date : Show the current date and time
  - cal : Show this month calendar
  - w : Display who is online
  - whoami : Who you are logged in as
  - finger user : Display information about user
HARDWARE
- - dmesg : Detected hardware and boot messages
  - cat /proc/cpuinfo : CPU model
  - cat /proc/meminfo : Hardware memory
  - cat /proc/interrupts : Lists the number of interrupts per CPU per I/O device
  - lshw : Displays information on hardware configuration of the system
  - lsblk : Displays block device related information in Linux
  - free -m : Used and free memory (-m for MB)
  - lspci -tv : Show PCI devices
  - lsusb -tv : Show USB devices
  - dmidecode : Show hardware info from the BIOS
  - hdparm -i /dev/sda : Show info about disk sda
  - hdparm -tT /dev/sda : Do a read speed test on disk sda
  - badblocks -s /dev/sda : Test for unreadable blocks on disk sda USERS
  - id : Show the active user id with login and group
  - last : Show last logins on the system
  - who : Show who is logged on the system
  - groupadd admin : Add group “admin”
  - useradd -c “Sam” : g admin -m sam #Create user “sam”
  - userdel sam : Delete user sam
  - adduser sam : Add user “sam”
  - usermod : Modify user information
  - chgrp : Changes a users group
Networking
- - ip addr show : Display all network interfaces and ip address
  - ip address add 192.168.0.1 dev eth0 : Set ip address
  - ethtool eth0 : Linux tool to show ethernet status
  - mii-tool eth0 : Linux tool to show ethernet status
  - ping host : Send echo request to test connection
  - whois domain : Get who is information for domain
  - dig domain : Get DNS information for domain
  - dig -x host : Reverse lookup host
  - host google.com : Lookup DNS ip address for the name
  - hostname –i : Lookup local ip address
  - wget file : Download file
  - netstat -tupl : Listing all active listening ports
DISK USAGE
- - df –h : Show free space on mounted filesystems
  - df -i : Show free inodes on mounted filesystems
  - fdisk -l : Show disks partitions sizes and types
  - du -ah : Display disk usage in human readable form
  - du -sh : Display total disk usage on the current directory
  - findmnt : Displays target mount point for all filesystem
  - mount device-path mount-point : Mount a device
DIRECTORY TRAVERSE
- - cd .. : To go up one level of the directory tree
  - cd : Go to $HOME directory
  - cd /test : Change to /test directory
FILE COMMANDS
- - ls –al : Display all information about files/ directories
  - pwd : Show the path of current directory
  - mkdir directory-name : Create a directory
  - rm file-name : Delete file
  - rm -r directory-nam : Delete directory recursively
  - rm -f file-name : Forcefully remove file
  - rm -rf directory-name : Forcefully remove directory recursively
  - cp file1 file2 : Copy file1 to file2
  - cp -r dir1 dir2 : Copy dir1 to dir2, create dir2 if it doesn’t exist
  - mv file1 file2 : Rename source to dest / move source to directory
  - ln –s /path/to/file-name link-name :Create symbolic link to file-name
  - touch file : Create or update file
  - cat > file : Place standard input into file
  - more file : Output contents of file
  - head file : Output first 10 lines of file
  - tail file : Output last 10 lines of file
  - tail -f file :Output contents of file as it grows starting with the last 10 lines
  - gpg -c file : Encrypt file
  - gpg file.gpg : Decrypt file
  - wc :print the number of bytes, words, and lines in files
  - xargs : Execute command lines from standard input
    PROCESS RELATED
  - ps : Display your currently active processes
  - ps aux | grep ‘telnet’ :Find all process id related to telnet process
  - pmap : Memory map of process
  - top : Display all running processes
  - kill pid : Kill process with mentioned pid id
  - killall proc : Kill all processes named proc
  - pkill process-name : Send signal to a process with its name
  - bg : Resumes suspended jobs without bringing them toforeground
  - fg : Brings the most recent job to foreground
FILE PERMISSION RELATED
- - chmod octal file-name : Change the permissions of file to octal
    - Example
    - chmod 777 /data/test.c :Set rwx permission for owner,group,world
    - chmod 755 /data/test.c :Set rwx permission for owner, rx for group and world
  - chown owner-user file : Change owner of the file
  - chown owner-user:owner-group file-name : Change owner and group owner of the file
  - chown owner-user:owner-group directory : Change owner and group owner of the directory
COMPRESSION / ARCHIVES
- - tar cf home.tar home : Create tar named home.tar containing home/
  - tar xf file.tar : Extract the files from file.tar
  - tar czf file.tar.gz files : Create a tar with gzip compression
  - gzip file : Compress file and renames it to file.gz
INSTALL PACKAGE
- - rpm -i pkgname.rpm =>Install rpm based package
  - rpm -e pkgname =>Remove package
  - INSTALL FROM SOURCE
    ./configure
    make
    make install
SEARCH
- - grep pattern files : Search for pattern in files
  - grep -r pattern dir : Search recursively for pattern in dir
  - locate file =>Find all instances of file
  - find /home/tom -name ‘index*’ : Find files names that start with “index”
  - find /home -size +10000k : Find files larger than 10000k in /home
LOGIN (SSH AND TELNET)
- - ssh user@host : Connect to host as user
  - ssh -p port user@host : Connect to host using specific port
  - telnet host : Connect to the system using telnet port
FILE TRANSFER
- - sftp 192.16875.2 : Connect remote host
  - scp
    scp file.txt server2:/tmp : Secure copy file.txt to remote host /tmp folder
  - rsync
    rsync -a /home/apps /backup/ : Synchronize source to destination

Reference

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Linux Basic Commands

Reference

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