Linux cheat-sheet
- 1. 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 NETWORK ip addr show =>Display all network interfaces and ip address (a iproute2 command,powerful than ifconfig) 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 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 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 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 SYSTEM uname -a =>Displaylinux 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 Tomshi" =>g admin -m sam #Create user "sam" userdel sam =>Delete user sam adduser sam =>Add user "sam" usermod =>Modify user information 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 to foreground fg =>Brings the most recent job to foreground fg n =>Brings job n to the foreground MORE DETAILED : HTTP://LINOXIDE.COM/GUIDE/LINUX-COMMAND-SHELF.HTML