Linux Cheat Sheets & Command References

Quick, practical Linux cheat sheets for system administrators and DevOps engineers. Bookmarkable command references covering filesystems, LVM, systemctl, storage, networking, and everyday Linux operations.

File & Directory Management

Command	Description
`ls`	List files and directories in the current location
`ls -l`	Display files with permissions, owner, size, and timestamp
`ls -a`	Include hidden files starting with dot
`ls -lh`	Show file sizes in human-readable format
`tree`	Display directory structure in a tree format
`cd /path`	Change current working directory
`pwd`	Print the absolute path of the current directory
`mkdir dir`	Create a new directory
`mkdir -p a/b/c`	Create nested directories in one command
`rmdir dir`	Remove an empty directory
`cp src dest`	Copy file from source to destination
`cp -r src dest`	Copy directories recursively
`mv src dest`	Move or rename files or directories
`rm file`	Delete a file
`rm -r dir`	Delete directory and its contents recursively
`rm -f file`	Force delete file without confirmation
`touch file`	Create an empty file or update timestamp
`stat file`	Show detailed file metadata
`ln src link`	Create a hard link
`ln -s src link`	Create a symbolic (soft) link

File Searching

Command	Description
`find /path -name file`	Search files by name in the specified directory path
`find /path -iname file`	Search filenames without considering letter case
`find /path -type f`	Find only regular files, excluding directories and links
`find /path -perm /4000`	Locate files that have the SUID permission bit set
`find /path -size +10M`	Find files larger than the specified size
`find /path -mtime -1`	Find files modified within the last 24 hours
`find /path -empty`	Locate empty files and empty directories
`find /path -links +1`	Find files that have more than one hard link
`locate file`	Quickly find files using the system locate database
`locate -i file`	Perform case-insensitive file search using locate
`locate -r regex`	Search files using regular expression patterns
`updatedb`	Update the database used by the locate command

Viewing & Paging Files

Command	Description
`cat file`	Display the entire contents of a file on the terminal
`less file`	View file content page by page with scroll and search support
`more file`	View file content one screen at a time with limited navigation
`head file`	Show the first 10 lines of a file by default
`head -n 20 file`	Display the first 20 lines of the specified file
`tail file`	Show the last 10 lines of a file by default
`tail -n 20 file`	Display the last 20 lines of the specified file
`tail -f file`	Continuously monitor a file as new lines are appended, commonly used for logs

Text Processing

Command	Description
`grep pattern file`	Search for a specific text pattern inside a file
`grep -i pattern file`	Perform case-insensitive text search
`grep -r pattern dir`	Search recursively through all files in a directory
`grep -v pattern file`	Display lines that do not match the given pattern
`grep -A 3 pattern file`	Show three lines after each matching line
`grep -B 3 pattern file`	Show three lines before each matching line
`awk '{print $1}' file`	Print the first column from each line of a file
`awk -F: '{print $1}' file`	Use a custom field delimiter to extract columns
`sed 's/a/b/' file`	Replace the first occurrence of a pattern in each line
`sed -i 's/a/b/g' file`	Replace all occurrences in a file and save changes
`cut -d: -f1 file`	Extract a specific column using a delimiter
`sort file`	Sort the contents of a file alphabetically
`uniq`	Remove duplicate adjacent lines from sorted input
`wc -l file`	Count the number of lines in a file
`diff f1 f2`	Compare two files and show line-by-line differences
`tee file`	Write command output to both the terminal and a file

Permissions & Ownership

Command	Description
`chmod 755 file`	Set read, write, and execute permissions using numeric mode
`chmod -R 755 dir`	Recursively change permissions for all files and directories
`chmod u+x file`	Add execute permission for the file owner
`chown user file`	Change the owner of a file to the specified user
`chown user:group file`	Change both owner and group of a file
`chown -R user:group dir`	Recursively change ownership for a directory and its contents
`chgrp group file`	Change the group ownership of a file
`umask`	Display the default permission mask for new files and directories

Archiving & Compression

Command	Description
`tar -cvf a.tar files`	Create a tar archive containing specified files
`tar -xvf a.tar`	Extract files from a tar archive
`tar -czvf a.tar.gz files`	Create a gzip-compressed tar archive
`tar -xzvf a.tar.gz`	Extract files from a gzip-compressed tar archive
`gzip file`	Compress a file using the gzip compression algorithm
`gunzip file.gz`	Decompress a gzip-compressed file
`zip a.zip files`	Create a zip archive from one or more files
`zip -r a.zip dir`	Compress a directory recursively into a zip archive
`unzip a.zip`	Extract files from a zip archive

Networking

Command	Description
`ping host`	Test network connectivity to a remote host
`ip a`	Display IP addresses and network interface details
`ip link`	Show available network interfaces and their state
`ip r`	Display the system routing table
`ip neigh`	Show ARP or neighbor cache entries
`ip route get IP`	Show the network route used to reach a destination
`ss -tuln`	List all listening TCP and UDP ports
`ss -tanp`	Show active TCP connections with associated processes
`netstat -tulnp`	Display network connections using the legacy netstat tool
`ifconfig`	Display network interface configuration (deprecated)
`nmcli device status`	Show NetworkManager device connection status
`curl URL`	Fetch data from a URL or test HTTP endpoints
`wget URL`	Download files from a URL to the local system
`scp src dest`	Securely copy files between local and remote systems
`ssh user@host`	Log in to a remote system securely using SSH
`traceroute host`	Trace the network path packets take to a destination
`nslookup domain`	Query DNS servers for domain name information
`host domain`	Perform a simple DNS lookup for a domain
`nmcli con show`	List all configured network connections
`nmcli con show <name>`	Show detailed settings of a specific network connection
`nmcli con add ...`	Create a new NetworkManager connection profile
`nmcli con mod <name> ...`	Modify configuration settings of an existing connection
`nmcli con up <name>`	Activate and bring up a network connection
`nmcli dev disconnect <device>`	Disconnect or disable a specific network device
`nmcli con del <name>`	Delete an existing network connection profile
`nmcli con reload`	Reload NetworkManager connection configuration files

Process & System Monitoring

Command	Description
`ps aux`	Display all running processes with detailed information
`top`	Show a real-time, continuously updating process list
`htop`	Enhanced interactive process viewer with color and controls
`uptime`	Display system run time and average system load
`watch cmd`	Execute a command repeatedly and display the output
`jobs`	List jobs currently running in the background
`bg %job`	Resume a stopped job and run it in the background
`fg %job`	Bring a background or stopped job to the foreground
`kill PID`	Send a termination signal to gracefully stop a process
`kill -9 PID`	Forcefully terminate a process using SIGKILL
`nice -n 10 cmd`	Start a command with a lower CPU scheduling priority
`renice PID`	Change the priority of an already running process

Performance & Resource Monitoring

Command	Description
`free`	Display current system memory usage statistics
`free -h`	Show memory usage in human-readable format
`vmstat`	Report memory, CPU, and I/O performance statistics
`vmstat 1`	Refresh system statistics every second
`iostat`	Display disk input and output statistics
`iostat -xz 1`	Show extended disk performance metrics with live updates
`mpstat`	Display CPU usage statistics for each processor core
`pidstat`	Report performance statistics for individual processes
`sar`	View historical system performance data collected over time
`nproc`	Show the number of CPU cores available to the system
`nproc --all`	Display the total number of installed CPU cores

RPM Package Management

Command	Description
`rpm -qa`	List all RPM packages currently installed on the system
`rpm -q NAME`	Display the installed version of a specific package
`rpm -qi NAME`	Show detailed information about an installed package
`rpm -ql NAME`	List all files installed by a package
`rpm -qc NAME`	Display configuration files provided by the package
`rpm -qd NAME`	List documentation files included with the package
`rpm -q --changelog NAME`	Show the change history of the specified package
`rpm -q --scripts NAME`	Display scripts executed during package install or removal
`rpm -qf FILE`	Identify which installed package owns a given file
`rpm -qlp FILE.rpm`	List files contained inside an RPM package file

YUM Package Management

Command	Description
`yum list`	List all available and installed packages from configured repositories
`yum group list`	Display available package groups for bulk installation
`yum search KEYWORD`	Search repositories for packages matching a keyword
`yum info PACKAGENAME`	Show detailed information about a specific package
`yum install PACKAGENAME`	Install a package along with all required dependencies
`yum group install GROUPNAME`	Install a predefined group of related packages
`yum update`	Update all installed packages to their latest versions
`yum remove PACKAGENAME`	Remove an installed package from the system
`yum history`	Display the transaction history of package operations

Disk & Filesystem

Command	Description
`df -h`	Show disk usage per filesystem in human-readable format
`df -i`	Display inode usage for each mounted filesystem
`du -sh dir`	Show total disk space used by a directory
`du -x`	Display disk usage only on the same filesystem
`lsblk`	List block devices and their hierarchy
`lsblk -f`	Show filesystem type, UUID, and mount points
`blkid`	Display block device attributes such as UUID and type
`mount dev dir`	Mount a filesystem to a directory
`mount \| column -t`	Display mounted filesystems in a readable table format
`mount \| grep ext4`	Filter and show only ext4 mounted filesystems
`mount UUID="<uuid>" /mnt/point`	Mount a filesystem using its UUID instead of the device name
`lsof /mnt/point`	Identify processes that are currently using a mount point
`umount dir`	Unmount a mounted filesystem
`findmnt`	Display mounted filesystems in a tree view
`fdisk -l`	List disk partitions and partition details
`parted print`	Show partition table information
`fsck dev`	Check and repair a filesystem
`resize2fs dev`	Resize an ext2/ext3/ext4 filesystem

Swap Management

Command	Description
`mkswap dev`	Create a swap area on the specified block device
`swapon dev`	Enable the specified swap device or partition
`swapoff dev`	Disable the specified swap device or partition

LVM (Logical Volume Management)

Command	Description
`pvs`	List all physical volumes
`pvcreate dev`	Initialize a block device as a physical volume
`pvdisplay`	Show detailed information about physical volumes
`vgs`	List all volume groups
`vgcreate vg pv`	Create a new volume group using a physical volume
`vgextend vg pv`	Add a physical volume to an existing volume group
`vgreduce vg pv`	Remove a physical volume from a volume group
`vgdisplay`	Display detailed information about volume groups
`lvs`	List all logical volumes
`lvcreate -L -n lv vg`	Create a logical volume with specified size and name
`lvextend -l +100%FREE /dev/vg01/lv01`	Extend the logical volume using all remaining free space in the volume group
`lvextend -L 10G /dev/vg01/lv01`	Resize the logical volume to a total size of 10 GiB
`lvextend -l +128 /dev/vg01/lv01`	Increase the logical volume by 128 physical extents
`resize2fs /dev/vg01/lv01`	Resize an ext4 filesystem to match the logical volume size
`xfs_growfs /mount/point`	Expand an XFS filesystem after extending the logical volume
`lvreduce -L 5G /dev/vg01/lv01`	Reduce the logical volume size to 5 GiB (filesystem must be resized first)
`lvreduce -L -2G /dev/vg01/lv01`	Shrink the logical volume by 2 GiB
`lvdisplay`	Show detailed information about logical volumes
`lvremove lv`	Delete a logical volume

Firewalld

Command	Description
`firewall-cmd --get-default-zone`	Display the default firewall zone
`firewall-cmd --get-active-zones`	Show all currently active firewall zones
`firewall-cmd --add-service=http`	Allow an HTTP service temporarily until reboot
`firewall-cmd --add-port=80/tcp`	Open TCP port 80 temporarily in the active zone
`firewall-cmd --permanent --add-port=80/tcp`	Open TCP port 80 permanently across reboots
`firewall-cmd --runtime-to-permanent`	Save current runtime firewall rules permanently
`firewall-cmd --reload`	Reload firewall rules without interrupting connections
`firewall-cmd --zone=public --list-all`	Display full configuration of the public firewall zone

SELinux

Command	Description
`getenforce`	Display the current SELinux mode (Enforcing, Permissive, or Disabled)
`setenforce 0`	Switch SELinux to permissive mode temporarily
`setenforce 1`	Enable SELinux enforcing mode immediately
`semanage port -l`	List all ports and their associated SELinux types
`semanage fcontext -l`	Display SELinux file context rules
`restorecon -Rv /path`	Restore default SELinux security labels recursively

systemd, Logs & Boot

Command	Description
`systemctl status svc`	Check the current status of a system service
`systemctl start svc`	Start a system service immediately
`systemctl stop svc`	Stop a running system service
`systemctl restart svc`	Restart a system service
`systemctl enable svc`	Enable a service to start automatically at boot
`systemctl disable svc`	Disable a service from starting at boot
`systemctl is-enabled svc`	Check whether a service is enabled at boot
`systemctl list-units --type=service`	List all active system services
`systemctl get-default`	Show the default system boot target
`systemctl set-default target`	Set the default boot target
`loginctl list-users`	List users currently logged into the system
`loginctl session-status`	Display detailed information about user sessions

systemd Journal (journalctl)

Command	Description
`journalctl`	Display the complete systemd journal containing all available logs
`journalctl -n`	Show the most recent log entries using the default count
`journalctl -n 5`	Display only the last five log entries
`journalctl -f`	Follow journal logs in real time, similar to tail -f
`journalctl -p err`	Show log messages with error priority and higher
`journalctl -xe`	View recent critical logs with detailed explanations
`journalctl -u svc`	View logs related to a specific service
`journalctl --since today`	Show logs generated since the beginning of today
`journalctl --since "YYYY-MM-DD HH:MM:SS"`	Display logs starting from a specific date and time
`journalctl --until "YYYY-MM-DD HH:MM:SS"`	Display logs up to a specific date and time
`journalctl --since "-1 hour"`	Show logs generated within the last one hour
`journalctl -o verbose`	Display logs with detailed metadata and fields
`journalctl _COMM=sshd`	Filter logs by command or process name
`journalctl _EXE=/usr/sbin/sshd`	Filter logs by full executable path
`journalctl _PID=1182`	Show logs generated by a specific process ID
`journalctl _UID=0`	Show logs generated by a specific user ID
`journalctl _SYSTEMD_UNIT=sshd.service`	Display logs for a specific systemd service
`journalctl _SYSTEMD_UNIT=sshd.service _PID=1182`	Combine multiple filters for precise log searching
`journalctl -p debug`	Show debug-level log messages and above
`journalctl -p info`	Show informational log messages and above
`journalctl -p notice`	Show normal but significant log messages
`journalctl -p warning`	Show warning-level log messages
`journalctl -p crit`	Show critical condition log messages
`journalctl -p alert`	Show alert-level logs requiring immediate attention
`journalctl -p emerg`	Show emergency-level logs when the system is unusable
`/run/log/journal`	Default volatile journal storage location on RHEL 8 (cleared on reboot)

Debugging & Tracing

Command	Description
`strace cmd`	Trace system calls made by a command
`strace -p PID`	Attach strace to an already running process
`strace -f cmd`	Trace system calls of child processes as well
`strace -c cmd`	Display a summary of system call usage
`strace -o file cmd`	Save system call trace output to a file
`lsof`	List all open files and associated processes
`lsof -i`	Show open network connections
`lsof -i :80`	Display processes using TCP or UDP port 80
`lsof -u user`	List files opened by a specific user
`lsof +D /path`	Show open files under a given directory
`time cmd`	Measure the execution time of a command
`/usr/bin/time -v cmd`	Display detailed resource usage statistics
`perf stat cmd`	Show performance counter statistics for a command
`perf top`	Display real-time CPU performance profiling
`perf record cmd`	Record performance data for later analysis
`perf report`	Analyze and display recorded performance data

Containers (Podman)

Command	Description
`podman pull image`	Download a container image from a registry
`podman images`	List all container images stored locally
`podman run`	Create and run a new container from an image
`podman ps -a`	List all containers, including stopped ones
`podman stop ctr`	Stop a running container gracefully
`podman rm ctr`	Remove a stopped container
`podman logs ctr`	View logs generated by a container
`podman exec -it ctr bash`	Open an interactive shell inside a running container
`podman inspect ctr`	Display detailed configuration and status information
`podman generate systemd`	Generate a systemd service unit for a container

Shell, Bash & Environment

Command	Description
`echo text`	Print text or variables to standard output
`env`	Display all current environment variables
`export VAR=value`	Set and export an environment variable
`unset VAR`	Remove an environment variable
`alias ll='ls -l'`	Create a shell alias for a command
`source file`	Execute a script in the current shell session
`bash script.sh`	Run a Bash script in a new shell process
`read var`	Read user input and store it in a variable
`history`	Display previously executed commands
`history \| grep cmd`	Search command history for a specific command
`!!`	Repeat the most recently executed command
`!$`	Reuse the last argument from the previous command
`set -x`	Enable shell debug mode to trace command execution
`set +x`	Disable shell debug mode
`exit`	Exit the current shell session

I/O Redirection

Command	Description
`cmd > file`	Redirect standard output to a file, overwriting existing content
`cmd >> file`	Append standard output to the end of a file
`cmd 2> file`	Redirect standard error output to a file
`cmd &> file`	Redirect both standard output and standard error to a file

Linux (Bash) Keyboard Shortcuts

Shortcut	Description
`Ctrl + A`	Move cursor to beginning of the line
`Ctrl + E`	Move cursor to end of the line
`Ctrl + B`	Move cursor back one character
`Ctrl + F`	Move cursor forward one character
`Alt + B`	Move cursor back one word
`Alt + F`	Move cursor forward one word
`Ctrl + U`	Delete from cursor to start of the line
`Ctrl + K`	Delete from cursor to end of the line
`Ctrl + W`	Delete the word before the cursor
`Ctrl + Y`	Paste the last deleted text
`Ctrl + L`	Clear the terminal screen
`Ctrl + C`	Terminate the currently running command
`Ctrl + R`	Search command history in reverse
`Ctrl + G`	Exit history search mode
`Ctrl + P`	Show the previous command
`Ctrl + N`	Show the next command

VI / VIM – Essential Command

Command	Description
`i`	Insert text before the cursor
`a`	Insert text after the cursor
`A`	Insert text at the end of the line
`o`	Insert a new line below the current line
`Esc`	Return to normal mode
`R`	Enter replace mode (overwrite text)
`r<char>`	Replace a single character
`[N]r<char>`	Replace N characters
`s`	Replace character and enter insert mode
`[N]s`	Replace N characters and enter insert mode
`/pattern`	Search forward for pattern
`x`	Delete the character under the cursor
`[N]x`	Delete N characters
`dd`	Delete the current line
`[N]dd`	Delete N lines
`D`	Delete from cursor to end of the line
`dw`	Delete the next word
`[N]dw`	Delete the next N words
`cw`	Change (replace) the current word
`[N]cw`	Change the next N words
`S`	Delete the current line and enter insert mode
`[N]S`	Delete N lines and enter insert mode
`C`	Change text from cursor to end of the line
`yy`	Yank (copy) the current line
`[N]yy`	Yank N lines
`p`	Paste text below the cursor
`P`	Paste text above the cursor
`u`	Undo the last change
`[N]u`	Undo the last N changes
`Ctrl + R`	Redo the last undone change
`[N]Ctrl + R`	Redo N changes
`U`	Restore the current line to its original state
`v`	Enter visual mode to select text
`y`	Yank (copy) selected text
`d`	Delete selected text
`~`	Toggle case of the character
`[N]~`	Toggle case for N characters
`:w`	Save the file
`:q`	Quit Vim
`:q!`	Quit without saving changes
`:wq`	Save the file and quit
`:x`	Save and quit (same as :wq)
`:set nu`	Show line numbers
`:set nonu`	Hide line numbers
`:%s/old/new/g`	Replace all occurrences of a word in the file
`:N`	Go to line number N

Stratis Storage Management

Command	Description
`yum install stratis-cli stratisd`	Install Stratis management tools and the Stratis daemon
`systemctl enable --now stratisd`	Enable and start the Stratis daemon immediately and at boot
`stratis pool create pool1 /dev/vdb`	Create a new Stratis storage pool using a block device
`stratis pool add-data pool1 /dev/vdc`	Add an additional block device to an existing Stratis pool
`stratis pool list`	Display all configured Stratis storage pools
`stratis filesystem create pool1 fs1`	Create a filesystem inside a Stratis storage pool
`stratis filesystem list`	List all Stratis filesystems
`stratis filesystem snapshot pool1 fs1 snap1`	Create a snapshot of an existing Stratis filesystem
`lsblk --output=UUID /stratis/pool1/fs1`	Display the UUID of a Stratis filesystem

VDO (Virtual Data Optimizer)

Command	Description
`yum install vdo kmod-kvdo`	Install VDO software and the required kernel module
`vdo create --name=vdo1 --device=/dev/vdd --vdoLogicalSize=50G`	Create a VDO volume with a logical size larger than the physical device
`vdo status --name=vdo1`	Display the current status of a VDO volume
`vdo list`	List all configured VDO volumes
`vdo start --name=vdo1`	Start a VDO volume
`vdo stop --name=vdo1`	Stop a VDO volume
`vdostats --verbose`	Show detailed VDO space usage, compression, and deduplication savings

autofs (Automatic Mounting)

Command / Configuration	Description
`/shares /etc/auto.demo`	Indirect map that dynamically creates directories under `/shares`
`/- /etc/auto.direct`	Direct map defining absolute mount points
`* -rw server:/path/&`	Wildcard map for dynamically mounting multiple directories

Power & System Control

Command	Description
`shutdown -h now`	Shut down the system immediately and power it off
`reboot`	Reboot the system immediately
`poweroff`	Power off the machine safely

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