Linux Commands A - Z

Linux Commands A - Z

Mastering Linux: A Comprehensive Guide to Commands from A to Z

Linux, known for its stability, security, and versatility, powers everything from personal computers to servers and embedded systems. Central to harnessing the full potential of Linux is a solid understanding of its command-line interface (CLI), which allows users to perform a wide array of tasks efficiently and precisely. Whether you're a beginner eager to explore the basics or an experienced user aiming to refine your skills, this guide will provide a thorough overview of essential Linux commands from A to Z.

In this article, we will embark on a journey through the vast landscape of Linux commands, presenting a detailed and structured compendium that covers commands ranging from basic file operations to advanced system administration tasks. Each command is accompanied by a brief description to help you understand its purpose and usage, making this guide an invaluable resource for anyone looking to navigate the Linux operating system with confidence.

Key Highlights:

• A to Z Coverage: A comprehensive list of commands, ensuring no essential tool is overlooked.
• Brief Descriptions: Concise explanations of each command to quickly grasp its functionality.
• Versatile Applications: Commands that cater to various use cases, from everyday tasks to specialized operations.
• User-Friendly Approach: Suitable for users at all levels, from newcomers to seasoned professionals.

By the end of this guide, you will have a well-rounded understanding of Linux commands, empowering you to leverage the full capabilities of your system. Whether you're managing files, troubleshooting issues, or automating processes, this alphabetical tour of Linux commands will enhance your command-line proficiency and productivity.

from: https://intitute.blogspot.com/2018/10/linux-commands-z.html

 A

• apropos : Search Help manual pages (man -k)
• apt-get : Search for and install software packages (Debian/Ubuntu)
• aptitude : Search for and install software packages (Debian/Ubuntu)
• aspell : Spell Checker
• awk : Find and Replace text, database sort/validate/index

B

• basename : Strip directory and suffix from filenames
• bash : GNU Bourne-Again SHell
• bc : Arbitrary precision calculator language
• bg : Send to background
• break : Exit from a loop
• builtin : Run a shell builtin
• bzip2 : Compress or decompress named file(s)

C

• cal : Display a calendar
• case : Conditionally perform a command
• cat : Concatenate and print (display) the content of files
• cd : Change Directory
• cfdisk : Partition table manipulator for Linux
• chgrp : Change group ownership
• chmod : Change access permissions
• chown : Change file owner and group
• chroot : Run a command with a different root directory
• chkconfig : System services (runlevel)
• cksum : Print CRC checksum and byte counts
• clear : Clear terminal screen
• cmp : Compare two files
• comm : Compare two sorted files line by line
• command : Run a command – ignoring shell functions •
• continue : Resume the next iteration of a loop •
• cp : Copy one or more files to another location
• cron : Daemon to execute scheduled commands
• crontab : Schedule a command to run at a later time
• csplit : Split a file into context-determined pieces
• cut : Divide a file into several parts

D

• date : Display or change the date & time
• dc : Desk Calculator
• dd : Convert and copy a file, write disk headers, boot records
• ddrescue : Data recovery tool
• declare : Declare variables and give them attributes •
• df : Display free disk space
• diff : Display the differences between two files
• diff3 : Show differences among three files
• dig : DNS lookup
• dir : Briefly list directory contents
• dircolors : Colour setup for `ls’
• dirname : Convert a full pathname to just a path
• dirs : Display list of remembered directories
• dmesg : Print kernel & driver messages
• du : Estimate file space usage

E

• echo : Display message on screen •
• egrep : Search file(s) for lines that match an extended expression
• eject : Eject removable media
• enable : Enable and disable builtin shell commands •
• env : Environment variables
• ethtool : Ethernet card settings
• eval : Evaluate several commands/arguments
• exec : Execute a command
• exit : Exit the shell
• expect : Automate arbitrary applications accessed over a terminal
• expand : Convert tabs to spaces
• export : Set an environment variable
• expr : Evaluate expressions

F

• false : Do nothing, unsuccessfully
• fdformat : Low-level format a floppy disk
• fdisk : Partition table manipulator for Linux
• fg : Send job to foreground
• fgrep : Search file(s) for lines that match a fixed string
• file : Determine file type
• find : Search for files that meet a desired criteria
• fmt : Reformat paragraph text
• fold : Wrap text to fit a specified width.
• for : Expand words, and execute commands
• format : Format disks or tapes
• free : Display memory usage
• fsck : File system consistency check and repair
• ftp : File Transfer Protocol
• function : Define Function Macros
• fuser : Identify/kill the process that is accessing a file

G

• gawk : Find and Replace text within file(s)
• getopts : Parse positional parameters
• grep : Search file(s) for lines that match a given pattern
• groupadd : Add a user security group
• groupdel : Delete a group
• groupmod : Modify a group
• groups : Print group names a user is in
• gzip : Compress or decompress named file(s)

H

• hash : Remember the full pathname of a name argument
• head : Output the first part of file(s)
• help : Display help for a built-in command
• history : Command History
• hostname : Print or set system name

I

• iconv : Convert the character set of a file
• id : Print user and group id’s
• if : Conditionally perform a command
• ifconfig : Configure a network interface
• ifdown : Stop a network interface
• ifup : Start a network interface up
• import : Capture an X server screen and save the image to file
• install : Copy files and set attributes

J

• jobs : List active jobs
• join : Join lines on a common field

K

• kill : Stop a process from running
• killall : Kill processes by name

L

• less : Display output one screen at a time
• let : Perform arithmetic on shell variables
• ln : Create a symbolic link to a file
• local : Create variables
• locate : Find files
• logname : Print current login name
• logout : Exit a login shell
• look : Display lines beginning with a given string
• lpc : Line printer control program
• lpr : Off line print
• lprint : Print a file
• lprintd : Abort a print job
• lprintq : List the print queue
• lprm : Remove jobs from the print queue
• ls : List information about file(s)
• lsof : List open files

M

• make : Recompile a group of programs
• man : Help manual
• mkdir : Create new folder(s)
• mkfifo : Make FIFOs (named pipes)
• mkisofs : Create an hybrid ISO9660/JOLIET/HFS filesystem
• mknod : Make block or character special files
• more : Display output one screen at a time
• mount : Mount a file system
• mtools : Manipulate MS-DOS files
• mtr : Network diagnostics (traceroute/ping)
• mv : Move or rename files or directories
• mmv : Mass Move and rename (files)

N

• netstat : Networking information
• nice Set : the priority of a command or job
• nl Number : lines and write files
• nohup : Run a command immune to hangups
• notify-send : Send desktop notifications
• nslookup : Query Internet name servers interactively

O

• open : Open a file in its default application
• op : Operator access

P

• passwd : Modify a user password
• paste : Merge lines of files
• pathchk : Check file name portability
• ping : Test a network connection
• pkill : Stop processes from running
• popd : Restore the previous value of the current directory
• pr : Prepare files for printing
• printcap : Printer capability database
• printenv : Print environment variables
• printf : Format and print data •
• ps : Process status
• pushd : Save and then change the current directory
• pwd : Print Working Directory

Q

• quota : Display disk usage and limits
• quotacheck : Scan a file system for disk usage
• quotactl : Set disk quotas

R

• ram : ram disk device
• rcp : Copy files between two machines
• read : Read a line from standard input
• readarray : Read from stdin into an array variable
• readonly : Mark variables/functions as readonly
• reboot : Reboot the system
• rename : Rename files
• renice : Alter priority of running processes
• remsync : Synchronize remote files via email
• return : Exit a shell function
• rev : Reverse lines of a file
• rm : Remove files
• rmdir : Remove folder(s)
• rsync : Remote file copy (Synchronize file trees)

S

• screen : Multiplex terminal, run remote shells via ssh
• scp : Secure copy (remote file copy)
• sdiff : Merge two files interactively
• sed : Stream Editor
• select : Accept keyboard input
• seq : Print numeric sequences
• set: Manipulate shell variables and functions
• sftp : Secure File Transfer Program
• shift : Shift positional parameters
• shopt : Shell Options
• shutdown : Shutdown or restart linux
• sleep : Delay for a specified time
• slocate : Find files
• sort : Sort text files
• source : Run commands from a file `.’
• split : Split a file into fixed-size pieces
• ssh : Secure Shell client (remote login program)
• strace : Trace system calls and signals
• su : Substitute user identity
• sudo : Execute a command as another user
• sum : Print a checksum for a file
• suspend : Suspend execution of this shell
• symlink : Make a new name for a file
• sync : Synchronize data on disk with memory

T

• tail : Output the last part of file
• tar : Tape ARchiver
• tee : Redirect output to multiple files
• test : Evaluate a conditional expression
• time : Measure Program running time
• times : User and system times
• touch : Change file timestamps
• top : List processes running on the system
• traceroute : Trace Route to Host
• trap : Run a command when a signal is set(bourne)
• tr : Translate, squeeze, and/or delete characters
• true : Do nothing, successfully
• tsort : Topological sort
• tty : Print filename of terminal on stdin
• type : Describe a command

U

• ulimit : Limit user resources
• umask : Users file creation mask
• umount : Unmount a device
• unalias : Remove an alias
• uname : Print system information
• unexpand : Convert spaces to tabs
• uniq : Uniquify files
• units : Convert units from one scale to another
• unset : Remove variable or function names
• unshar : Unpack shell archive scripts
• until : Execute commands (until error)
• uptime : Show uptime
• useradd : Create new user account
• userdel : Delete a user account
• usermod : Modify user account
• users : List users currently logged in
• uuencode : Encode a binary file
• uudecode : Decode a file created by uuencode

V

• v : Verbosely list directory contents (`ls -l -b’)
• vdir : Verbosely list directory contents (`ls -l -b’)
• vi : Text Editor
• vmstat : Report virtual memory statistics

W

• wait : Wait for a process to complete
• watch : Execute/display a program periodically
• wc : Print byte, word, and line counts
• whereis : Search the user’s $path, man pages and source files for a program
• which : Search the user’s $path for a program file
• while : Execute commands
• who : Print all usernames currently logged in
• whoami : Print the current user id and name (`id -un’)
• wget : Retrieve web pages or files via HTTP, HTTPS or FTP
• write : Send a message to another user

x

• xargs : Execute utility, passing constructed argument list(s)
• xdg-open : Open a file or URL in the user’s preferred application.