Basic Commands and Command Line Shortcuts That Every Linux Users Should Know
Here are the commands that can be used through command line windows such as Terminal, Console, or any terminal program under X-windows (x-term, rxvt, aterm, etc.).
Note that some of these key commands are specific to command line windows and may behave differently depending on your window manager under X.
Terminal, also known as GNOME Terminal, is the command line tool of the GNOME desktop environment.
Software such as GNOME Terminal, which connects to the command line through a window manager, is generally referred to as “terminal.” These are also termed “console, shell, terminal emulator.”
Console is a classical terminal emulator developed as part of the KDE project. Konsole is distinguished from other terminals by being almost completely rewritten (not based on xterm or rxvt).
Komut Satırı Kısayol Tuşları
| Komut | Description |
|---|---|
| Ctrl + Alt + F1 | Switch to the next terminal. |
| Ctrl + Alt + T | Open a terminal window. |
| Ctrl + Shift + W | Close the terminal window. |
| Ctrl + A | Move the cursor to the beginning of the command line without erasing text. |
| Ctrl + E | Move the cursor to the end of the command line without erasing text. |
| Alt + F | Move the cursor to the end of the word. |
| Alt + B | Move the cursor to the beginning of the word. |
| Ctrl + F | Move the cursor forward by one character. |
| Ctrl + B | Move the cursor backward by one character. |
| Ctrl + U | Cut text from the cursor position to the beginning of the line (add to clipboard). |
| Ctrl + Y | Paste the last cut text at the cursor position. |
| Ctrl + W | Delete text before the cursor up to the beginning of the word, without affecting other words. |
| Ctrl + K | Cut text from the cursor position to the end of the line (add to clipboard). |
| Alt + T | Swap the two words before the cursor if the cursor is on a space, or the word under the cursor with the word before it. |
| Alt + L | Convert all characters after the cursor to lowercase. |
| Alt + U | Convert all characters after the cursor to uppercase. |
| Alt + C | Capitalize the letter under the cursor and move the cursor to the end of the word. |
| Alt + D | Cut text from the cursor position to the end of the word. |
| Alt + . | Insert the last word of the previous command. |
| Ctrl + T | Swap the two characters before the cursor. |
| Ctrl + R | Search for previously used commands. |
| Ctrl + G | Exit search mode without selecting a command. |
| Ctrl + J | Copy a command found with Ctrl + R without executing it, allowing modifications. |
| Alt + R | Undo changes to a command found with Ctrl + R; pressing again will redo the changes. |
| Ctrl + P | Recall previous commands in the command history (same as the up arrow key). |
| Ctrl + N | Move forward in the command history (same as the down arrow key). |
| Ctrl + L | Clear the screen (same as the clear command). |
| Ctrl + Alt + F7 | Return to the X session previously exited with Ctrl + Alt + F1. |
| Ctrl + Alt + Del | Reboot the system (like the shutdown command). Use this instead of the reset button. |
| Ctrl + C | Terminate the current command (usually for simple commands). |
| Ctrl + D | Send EOF (end-of-file) if a command is accepting input; logout if at the prompt. Do not press twice (logs out of the current shell session). |
| Ctrl + S | Stop the output of a long-running command (command continues to run). |
| Ctrl + Q | Resume output after stopping it with Ctrl + S. |
| Ctrl + Z | Suspend the current command; it can be resumed in the background with bg or in the foreground with fg. Use jobs to view suspended programs. |
| Shift + Insert | Paste text from the clipboard. |
Basic Linux Commands
Important and essential Linux commands to remember.
System Commands
- uname -u: System information (kernel version, date, and architecture)
- uname -r: Kernel version information
- uptime: Show how long the system has been running and the load
- hostname: Show the system name
- last reboot: List of recent reboots including changes in run levels
- date: Display the current date and time
- cal: Show the calendar
- w: Show who is logged on and what they are doing
- whoami: Show the current user name
- finger user: Show information about the user
-
**echo “user” chpasswd:** Change a password in one line
Hardware Commands
- dmesg: Print kernel messages
- cat /proc/cpuinfo: Show CPU information
- cat /proc/meminfo: Show memory (RAM) information
- cat /proc/interrupts: Show the interrupt usage of the CPU
- lshw: List hardware configuration information
- lsblk: List block devices
- free -m: Show memory usage
- lspci -tv: List PCI devices
- lsusb -tv: List USB devices
- dmidecode: Show BIOS hardware information
- hdparm -i /dev/sda: Show information about a disk
- hdparm -tT /dev/sda: Run a read speed test on a disk
- badblocks -s /dev/sda: Check for bad blocks on a disk
Users
- cat /etc/passwd: List all users
- id: Show user ID information
- last: Show the list of users who last logged in
- who: Show who is currently logged in
- groupadd: Create a new group
- useradd user: Add a new user named “user”
- userdel user: Delete the user named “user”
- usermod: Modify user permissions
File Commands
- ls -la: List files (a for all files, l for long format)
- pwd: Show the current directory
- mkdir: Create a directory
- rm: Delete a file
- rm -r: Delete a directory and its contents
- rm -f: Force delete without confirmation
- rm -rf: Force delete a directory and its contents without confirmation
- cp: Copy a file
- cp -r home1 home2: Copy the directory home1 to home2
- mv: Move files
- ln -s “/home/user/app” /usr/local/bin: Create a shortcut to an application
- touch: Create a file
- cat: Read the contents of a file
- more: Paginate the contents of a file
- head: Show the first 10 lines of a file
- tail: Show the last 10 lines of a file
- tail -f: Continuously display the last 10 lines of a file
Process Commands
- ps: Show running processes
-
**ps aux grep app:** Show processes related to the specified application - pmap -x PID: Show the memory map of a process
- top: Show the system status, including memory/CPU usage of running processes
- kill: Terminate a process
- killall: Terminate all processes with the specified name
- pkill -f telnet: Terminate processes matching the specified pattern
- bg: Resume a suspended job in the background
- fg: Bring a background job to the foreground
Permissions
- chattr +i filename: Make a file immutable (cannot be deleted)
- chattr -i filename: Remove immutability from a file
- chattr +a filename: Allow appending to a file only
- lsattr filename: Check attributes set by chattr
- chmod 777: Make a file readable, writable, and executable by everyone
- chmod 644: Make a file readable by everyone, writable by the owner
- chmod 755: Make a file readable and executable by everyone, writable by the owner
- chown owner-user: Change the owner of a file
- chown owner-user:owner-group Change the owner and group of a file
- chown -R user:directory/file: Give the user access to the file/directory
Network Commands
- ip addr show: Lists all network interfaces and shows their ip addresses
- ip address add 192.168.0.2 dev enp4so: Adds ip address to the specified interfaces
- **ip link set
up:** Activates the network interface. - **ip link set
down:** Disables the network interface. - ethool enp4s0: Gives information about the Ethernet status.
- ping 192.168.0.2: Sends an echo request to the specified ip address.
- dig example.com: Returns DNS information about the domain name.
- dig -x: Backwards search operation.
- host example.com: Gets the hostname and looks up the machine name.
- hostname -i: Shows the local ip address.
- wget: Downloads a file from the specified address.
- netstat -tulpn: Lists the ports that are actively listening.
- ip a: Lists the interfaces on the computer.
- echo ‘1’ > /proc/sys/net/ipv4/ip_forward: Activates IP Forwarding, turns the system into a router
- echo ‘1.1.1.1.1’ > /etc/resolv.onf: The system uses Cloudflare DNS.
Archiving Commands
- tar -cf homebackup.tar home: Creates an archive file named homebackup.tar
- tar -xf homebackup.tar: Parses the archive named homebackup.tar
- tar -czf homebackup.tar.gz home: Creates archive using gzip compression
- gzip home: Creates an archive file as home.gz
- unzip abc.zip: Extracts the zip file.
- zipgrep *.txt abcd.zip: Searches for txt files in Zipp
- tar xjf archive.tar.bz2: Extract tar.bz2 file
-
**tar ztvf home.tar.gz grep abc:** Searches tar.gz - gzip -d home.gz: Extracts the gzip file
- zgrep ‘abc’ /var/log/maillog*.gz: Allows you to search the log file without extracting it
Installation (Debian)
- apt-get install package_name: Installs the package on Debian-based systems
- apt-get purge package-name: Unpacks Debian-based systems
Compilation Commands
- **./configure
- **make
- **make install
Basically all compilation operations are done through these commands.
Search Commands
- find -name ‘yakup*’: Finds all files with yakup in the name
- find . -type f -size +100k: Searches for files larger than 100k
- find . -type f -size +100k -a -size -110k: Searches for files between 100k and 110k
- sed: Stream editor and text manipulation
- grep expression file: Searches for the expression in the file
- grep -r expression file: Recursively searches for the specified expression
- locate file: Searches for the specified file.
SSH
- ssh user@host: Connects to the specified machine
- ssh user@host -p port: Connects to the specified machine with the specified port
- telnet host: Connects to the machine via telnet port
File Transfer
- scp kullanıcı@host:aktarılıcakdosya.txt /home/yakup: Transfers files to the specified machine
- rsync -a /home/mertcan /backups: Provides synchronisation between source and destination
Disc Usage
- du -ah: Shows the space used by directories legibly
- du -sh: Shows the aggregate space used by the array
- df -h: Shows the latest status of the discs
- df -i: Empty inode status is displayed
- findmnt: Shows all connected directories in the file system in detail
- mount /dev/sda/ /mnt: Mount disc to /mnt
Index Commands
- cd: Navigates to the first level directory
- cd -: Returns to the previous directory
- cd ~: Switches to your home directory
- cd …: Navigates to the next directory
- cd directory: Navigates to the specified directory
Bonus
- history -c: Clears command line history
- clamscan -r -z - remove - verbose /home: Virus scanning and deletion
-
**du -h - max-depth=1 sort -hr:** Shows the total size of the directories - **find /home/mertcan/ -type -f -exec grep -H ‘yazi’ {} ; Searches for yazi in the directory
- dd if=debain.iso of=/dev/sdb: Burn iso to USB or DVD
- shred -verbose -random-source=/dev/zero -iterations=5 /dev/sda: Ultra-secure disc erase
- **find -type f -exec chmod 644 {} ; Sets all file permissions to 644.
- openvpn - config client.ovpn: Provides connection to the VPN server
- sensors: Returns the temperatures of hardware components.
- gcc -o output input.c: Compiles C code
- rdesktop x.x.x.x.x: Provides RDP connection
-
**ssh root@x.x.x.x cat /dev/null > ~/.bash_history:** Clears the bash history.
These commands are just a sample of what can be done via the command line in a Linux environment. For further details, consult the man pages of each command.
Ref: Yakup Şeker - Medium