Linux Commands
Last updated
Last updated
│ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │
I have prepared a help and manual for Linux, based on Ubuntu (cause other distribution are using same kernel the commands are mostly same). However, if you require specific guidance for a different Linux distribution, this resource can be helpful.
Accept or Reject jobs to a destination, such as a printer.
Check a user’s RWX(read, write and execute) permission for a file.
Used to turn on or turn off the process for accounting or change info process accounting file.
Used to automatically generate aclocal.m4 files from configure.in file.
Show information about the Advanced Configuration and Power Interface.
Used to convert addresses into file names and line numbers.
Formats for internet mail addresses.
An alternative Linux Getty that manages physical or virtual terminals to allow multi-user access.
Create an alias, a shortcut that references a command.
Access advanced controls for ALSA soundcard driver.
Perform read/write operation for ALSA RawMIDI ports.
Access CLI-based mixer for ALSA soundcard driver.
Used to run commands periodically.
Sound recorder and player for CLI.
CLI utility used to play MIDI files.
Show Advanced Power Management (APM) hardware info on older systems.
Used to handle events reported by APM BIOS drivers.
Shows the list of all man pages containing a specific keyword.
Command-line utility to install/remove/update packages based on APT system.
Advanced Package Tool, a package management system for Debian and derivatives.
Another utility to add/remove/upgrade packages based on the APT system.
A utility to create/modify/extract from archives.
Display print machine hardware name.
Just like aplay, it’s a sound recorder and player for ALSA(Advanced Linux Sound Architecture) soundcard driver.
Record standard MIDI files.
Used to make changes to the system’s ARP cache.
An interactive spell checker utility.
Used to schedule command execution at specified date & time, reading commands from an input file.
Used to execute jobs queued by the at command.
List a user’s pending jobs for the at command.
Delete jobs queued by the at command.
An audio mixer utility.
Generate configuration scripts from a TEMPLATE-FILE and send the output to standard output.
Create a template header for configure.
Creates GNU standards-compliant Makefiles from template files.
Update generated configuration files.
Generate a preliminary configure.in file.
Search a disk partition for bad sectors.
Used to print the ASCII character string in large letter to standard output
It strips directory information and suffixes from file names ie it prints the file name NAME with any leading directory components removed
Used to read commands from standard input or a specified file and execute them when system load levels permit ie when the load average drops below
Used for command line calculator
Used to place foreground jobs in background
A mail notification system for unix that notifies the user at the command line when new mail arrives and tells from whom it is
Used to set Readline key bindings and variables
It is basically a parser generator similar to yacc
Used to terminate the execution of for loop, while loop and until loop
Used to run a shell builtin, passing it arguments(args), and also to get the exit status
Used to invoke the cmp utility on bzip compressed files
Used to compare the bzip compressed files
Used to search for a pattern or an expression but inside a bzip-compressed file
Used to compress and decompress the files
Used to see the calendar of a specific month or a whole year By default, it shows current month’s calendar as output.
Used to control PCMCIA sockets and select configuration schemes.
Keeps an eye on the added/removes sockets for PCMCIA devices.
It is the best alternative when we had to use multiple if/elif on a single variable
cat - create, view and concatenate files
GNU C and C++ compiler.
cp - copy files and directories
cat - create, view and concatenate files
Used for encryption and decryption of data.
cd - change director
cd / ----> change to the root directory
cd ~ ----> change to your home directory
cd ----> change to your home directory
cd ----> change to the directory above your current ie parent directory
cd ----> change to the directory you currently in
cd - ----> change to the last visited path
Record audio from CD more reliably using data-verification algorithms.
Used to write all the content specified to a file to a CD all at once.
Show or change the disk partition table.
Used to view and change the user password expiry information
It is a file system command which is used for changing the attributes of a file in a directory
Used to change active working directory.
It allows you to change a user’s name and other details easily chfn stands for Change finger
Used to change the group ownership of a file or directory
Used to list all available services and view or update their run level settings
Change access permission for a file(s).
Change the owner or group for a file.
Update password in a batch.
Run a command with root directory.
Alter process attributed in real-time.
Used to change the user’s login shell(currently login shell)
Used to switch between the different TTY (TeleTYpewriter) terminals available
Used to display a CRC(Cyclic Redundancy Check) value, the byte size of the file and the name of the file to standard output
Used to compare the two files byte by byte and helps you to find out whether the two files are identical or not
Used to format the text processor output so that it can be viewed on Cathode Ray Tube displays
Remove columns from the lines of a file.
Used to display the contents of a file in columns
Compares two sorted files line by line and write to standard output; the lines that are common and the lines that are unique
Used to reduce the file size After compression, the file will be available with an added Z extension
Used to skip the current iteration in for, while and until loop
Copy contents of one file to another.
cpio stands for “copy in, copy out“ It is used for processing the archive files like *cpio or *tar This command can copy files to and from archives
A software utility, offered by Linux-like operating system which automates the scheduled task at a predetermined time
Same work as cron.
A list of commands that you want to run on a regular schedule, and also the name of the command used to manage that list.
Used to split any file into many parts as required by the user.
It allows quick access across the files (For example quickly seeing definition of a function)
It is a type of scheduler for CUPS (Common Unit Printing System) It implements the printing system on the basis of the Internet Printing Protocol
A tool to transfer data to or from a server, using any of the supported protocols
For cutting out the sections from each line of files and writing the result to standard output
Used to store the history of a file Whenever a file gets corrupted or anything goes wrong “cvs” help us to go back to the previous version and restore our file
Used to display the system date and time It is also used to set date and time of the system
Used to declare shell variables and functions, set their attributes and display their values
Used to generate a list of dependency description of kernel modules and its associated map files
It is a command-line utility for Unix and Unix-like operating systems whose primary purpose is to convert and copy files
Used to display the differences in the files by comparing the files line by line
Used to remove the trailing forward slahes “/” from the NAME and prints the remaining portion
Used to display the list of currently remembered directories
Used to stop the printers or classes
Used to examine the kernel ring buffer and print the message buffer of kernel
Used to return the Network Information System (NIS) domain name of the host
Used to retrieve information or statistics form components of the system such as network connections, IO devices, or CPU, etc
Used to backup the filesystem to some storage device
Used for the dump keyboard translation tables
It allows ejecting a removable media (typically a CD-ROM, floppy disk, tape, or JAZ or ZIP disk) using the software
It is a editor having simple user interface Also, there is no insert mode in this editor It only have editing mode
Used to start the printers or classes
Used to either print environment variables It is also used to run a utility or command in a custom environment
Built-in command used to execute arguments as a shell command
Used to exit the shell where it is currently running
Allows you to convert tabs into spaces in a file and when no file is specified it reads from standard input
This command or scripting language works with scripts that expect user inputs It automates the task by providing inputs
It is bash shell BUILTINS commands, which means it is part of the shell It marks an environment variables to be exported to child-processes
It evaluates a given expression and displays its corresponding output
Used to print the prime factors of the given numbers, either given from command line or read from standard input
Used to list, edit or re-execute the commands previously entered into an interactive shell
It is used to list the available fonts and font styles Using the format option, the list of all fonts can be filtered and sorted out
Used to put a background job in foreground
Used to determine the type of a file file type may be of human-readable(eg ‘ASCII text’) or MIME type(eg ‘text/plain; charset=us-ascii’)
Used to find files and directories and perform subsequent operations on them
It is a user information lookup command which gives details of all the users logged in
Works as a formatter for simplifying and optimizing text files
It wraps each line in an input file to fit a specified width and prints it to the standard output
Used to repeatedly execute a set of command for every element present in the list
Used to draw various type of patterns on the terminal
Used to create functions or methods
Used for pattern scanning and processing language
GNU Debugger tool helps to debug the programs written in C, C++, Ada, Fortran, etc
Used to get the entries in a number of important text files called databases
Used to administer the /etc/group and /etc/gshadow
Used to create a new user group
Used to delete a existing group
Used to modify or change the existing group on Linux system
Groups are the collection of users Groups make it easy to manage users with the same security and access privileges
It verifies the integrity of the groups information It checks that all entries in /etc/group and /etc/gshadow have the proper format and contain valid data
It is used to convert to shadow groups The grpconv command creates a gshadow from the group and an optionally existing gshadow
This command invokes Ghostscript, which is an interpreter of Adobe Systems PostScript and Portable Document Format(PDF) languages
Used to compress or expand a file or a list of files in Linux
Used to compress executable files and also used to automatically uncompress and execute the files
This command compresses files Each single file is compressed into a single file
Used to instruct the hardware to stop all the CPU functions Basically, it reboots or stops the system
Used to maintain a hash table of recently executed programs
Used to get statistics about the hard disk, alter writing intervals, acoustic management, and DMA settings
Used to filter and display the specified files, or standard input in a human readable specified format
Used to view the previously executed command
Used to displays the Host’s ID in hexadecimal format
Used to obtain the DNS(Domain Name System) name and set the system’s hostname or NIS(Network Information System) domain name
Provides a proper API used to control Linux system hostname and change its related settings
Utility for accessing the hardware clock, also called Real Time Clock (RTC)
Used to convert some text in one encoding into another encoding
Used to find out user and group names and numeric ID’s (UID or group ID) of the current user or any other user in the server
Used to execute commands based on conditions
Used to configure the kernel-resident network interfaces
It is a network analyzing tool used by system administrators to view the bandwidth related stats
It basically brings the network interface up, allowing it to transmit and receive dat
Used for capturing a screenshot for any of the active pages we have and it gives the output as an image file
Used to insert modules into the kernel
Used to copy files and set attributes
Used for monitoring system input/output statistics for devices and partitions
Used to display and monitor the disk IO usage details and even gets a table of existing IO utilization by the process
Used to remove some IPC(Inter-Process Communication) resources It eliminates the IPC objects and their associated data structure form the system
Used to display the parameters, and the wireless statistics which are extracted from /proc/net/wireless
Show the list of active jobs and their status.
It is a command line utility for joining lines of two files based on a key field present in both the files
Used to view systemd, kernel and journal logs
Used to terminate processes manually kill command sends a signal to a process which terminates the process
Used to display the list of all the users logged in and out since the file /var/log/wtmp was created
Used to evaluate arithmetic expressions on shell variables
ls - listing files and directories
Used to create links between files
Used to find the files by name
Shows the lines beginning with a given string
Used to display details about block devices and these block devices(Except ram disk) are basically those files that represent devices connected to the pc
Used to generate the detailed information of the system’s hardware configuration from various files in the /proc directory
Used to display the information about USB buses and the devices connected to them
This command in Linux prints the mail queue ie the list of messages that are there in the mail queue
mkdir - create directories
Used to display the information about a Linux Kernel module
Used to mount the filesystem found on a device to big tree structure(Linux filesystem) rooted at ‘/‘
Used to report processor related statistics
It is one of the powerful networking tool, security tool or network monitoring tool
Displays various network related information such as network connections, routing tables, interface statistics, masquerade connections, multicast memberships, etc
Used for controlling NetworkManager nmcli command can also be used to display network device status, create, edit, activate/deactivate, and delete network connections
It is a network administration tool for querying the Domain Name System (DNS) to obtain domain name or IP address mapping or any other specific DNS record
Used to join files horizontally (parallel merging) by outputting lines consisting of lines from each file specified, separated by tab as delimiter, to the standard output
Used to find out the process IDs of a specific running program
Used to check the network connectivity between host and server/host
pwd - print current working directory (= at what path the user currently located)
Used to display the given string, number or any other format specifier on the terminal window
Used to generate index to archive
Used to copy files from one computer to another computer
Reads up the total number of bytes from the specified file descriptor into the buffer
rm - remove files and directories
Used to get information of ELF(Executable and Linkable Format) Files
Used to print resolved symbolic links or canonical file names
Instructs the system to rest or reboot
Used to initialize the terminal This is useful once a program dies leaving a terminal in an abnormal state
Used for restoring files from a backup created using dump
Used to exit from a shell function
Used to reverse the lines characterwise
Used to remove a module from the kernel
Used when you want to work with the IP/kernel routing table
Provides the ability to launch and use multiple shell sessions from a single ssh session
Used to make typescript or record all the terminal activities
Used to compare two files and then writes the results to standard output in a side-by-side format
Used for finding, filtering, text substitution, replacement and text manipulations like insertion, deletion search etc
Used to create a numbered menu from which a user can select an option
Used to generate numbers from FIRST to LAST in steps of INCREMENT
Used to run a program in a new session
Shifts/moves the command line arguments to one position left
prints to standard output either the scan codes or the key code or the `ascii’ code of each key pressed
Used in order to delete a file completely from hard disk
Used to shutdown the system in a safe way
Used to create a dummy job A dummy job helps in delaying the execution
Used to read and execute the content of a file(generally set of commands), passed as an argument in the current shell script
Used to sort a file, arranging the records in a particular order
Used to split large files into smaller files
Protocol used to securely connect to a remote server/system
It is one of the most powerful process monitoring, diagnostic, instructional tool of Linux
Used to change and print terminal line settings
Used to find checksum and count the blocks in a file
Used to synchronize cached writes to persistent storage
Used to concatenate and print files in reverse
Prints the last N number of data of the given input
Used to create Archive and extract the Archive files
touch - update file's timestamp More commonly used for creating files
It is a command line utility for translating or deleting characters
Used to traces path to destination discovering MTU along this path
Prints the route that a packet takes to reach the host
It displays the information related to terminal It basically prints the file name of the terminal connected to standard input
Displays the information about the system
Converts each spaces into tabs writing the produced output to the standard output
It is a command line utility that reports or filters out the repeated lines in a file
Used to execute a set of commands as long as the final command in the ‘until’ Commands has an exit status which is not zero
Used to find out how long the system is active (running)
A text editor utility.
Set the video mode for a kernel image. Displays current mode value without arguments.
Vi Improved, a text-based editor which is a successor to vi.
It is a performance monitoring command of the system as it gives the information about processes, memory, paging, block IO, disk and CPU scheduling
Used by system administrators in order to monitor network parameters such as bandwidth consumption or maybe some traffic flowing in or out
Used to show who is logged on and what they are doing
Displays a message, or the contents of a file, or otherwise its standard input, on the terminals of all currently logged in users
Used to find out number of lines, word count, byte and characters count in the files specified in the file arguments
Used to download files from the server even when the user has not logged on to the system and it can work in background without hindering the current process
Used to execute a program periodically, showing output in fullscreen
Used to locate the executable file associated with the given command by searching it in the path environment variable
Used to repeatedly execute a set of command as long as the COMMAND returns true
Used to get information about currently logged in user on to system
Displays the username of the current user when this command is invoked
Allows a user to communicate with other users, by copying lines from one user’s terminal to others
Used to build and execute commands from standard input It converts input received from standard input into arguments of a command
Used to invoke the diff program on files compressed via gzip
Used to print the current time in the specified zone or you can say prints the current time in each zonename named on the command line
Used to search out expressions from a given a file even if it is compressed
It is a compression and file packaging utility for Unix Each file is stored in single zip {zip-filename} file with the extension zip