#FileOperation
#ls : List files in a directory.
#cp: Copy a file.
#mv: Rename (“move”) a file.
#rm: Delete (“remove”) a file.
#ln: Create links (alternative names) to a file.
#shred: Completely erase a file when the file is deleted
#DirectoryOperation
#cd: Change your current directory.
#pwd: Print the name of your current directory.
#basename: Print the final part of a file path.
#dirname: Print a file path without its final part.
#mkdir: Create (make) a directory.
#rmdir: Delete (remove) an empty directory.
#rm -r: Delete a nonempty directory and its contents.
#ViewingFiles
#cat: View files in their entirety. cat [filename]
#less: View text files one page at a time. less [filename]
#head: View the first lines of a text file. head [filename]
#tail: View the last lines of a text file. tail [filename]
#nl: View text files with their lines numbered. nl [filename]
#strings: Display text that’s embedded in a binary file. strings [filename]
#od: View data in octal (or other formats). oc [filename]
#xxd: View data in hexadecimal.xxx [filename]
#gv: View PostScript or PDF files. sudo apt install gv [filename]
#xdvi: View TeX DVI files. sudo apt install xdiv xdiv [filename]
#JobControl #commands
#jobs: List your jobs.
#&: Run a job in the background.
#^Z: Suspend the current (foreground) job.
#suspend: Suspend a shell.
#fg: Un-suspend a job: bring it into the foreground.
#bg: Make a suspended job run in the background.
#kill -STOP/-CONT : pausing continuing process
#FileCreation and #Editing
#Vim: Open file/ Create a File
#Vi : Open File/ Create a File.
#Nano : Open File/ Create a File
#Emacs : Open/Create File
#Edit: Graphical File Editor
#Ed: is a line-oriented text editor. It is used to create, display, modify and text files
#File Property Commands
#stat: Display attributes of files and directories.
#wc: Count bytes, words, lines in a file.
#du: Measure disk usage of files and directories.
#file: Identify (guess) the type of a file.
#touch: Change timestamps of files and directories.
#chown: Change owner of files and directories.
#chgrp: Change group ownership of files and directories.
#chmod: Change protection mode of files and directories.
#umask: Set a default mode for new files and directories.
#chattr: Change extended attributes of files and directories.
#lsattr: List extended attributes of files and directories.
#SearchingFiles #Location
#find: Locate files in a directory hierarchy.
#xargs: Process a list of located files (and much more).
#locate: Create an index of files, and search the index for string.
#which: Locate executables in your search path (command).
#type: Locate executables in your search path (bash built-in).
#whereis: Locate executables, documentation, and source files.
#File content manipulation
#grep: Find lines in a file that match a regular expression.
#cut: Extract columns from a file.
#paste: Append columns.
#tr: Translate characters into other characters.
#sort: Sort lines of text by various criteria.
#uniq: Locate identical lines in a file.
#tee: Copy a file and print it on standard output, simultaneously.
#File #Compression and #Packaging
#tar: Package multiple files into a single file.
#gzip: Compress files with GNU Zip.
#gunzip: Uncompress GNU Zip files.
#bzip2: Compress files in BZip format.
#bunzip2: Uncompress BZip files.
#bzcat: Compress/uncompress BZip files via standard input/output.
#compress: Compress files with traditional Unix compression.
#uncompress: Uncompress files with traditional Unix compression.
#zcat: Compress/uncompress file via standard input/output (gzip or compress).
#zip: Compress files in Windows Zip format.
#unzip: Uncompress Windows Zip files.
#metamail: Extract MIME data to files.
#Filescomparision
#diff: Line-by-line comparison of two files or directories.
#comm: Line-by-line comparison of two sorted files.
#cmp: Byte-by-byte comparison of two files.
#md5sum: Compute a checksum of the given files (MD5).
#Printer/#Printing
#lpr: Print a file.
#lpq: View the print queue.
#lprm: Remove a print job from the queue.
#Spelling Checking
#look: Look up the spelling of a word quickly.
#aspell: Interactive spelling checker.
#spell: Batch spelling checker.
#Disk and #FileSystem
#df: Show information about the file system on which each FILE resides, or all file systems by default.
#du : Summarize disk usage of the set of FILEs, recursively for directories.
#mount: Make a disk partition accessible.
#umount: Unmount a disk partition (make it inaccessible).
#fsck: Check a disk partition for errors.
#sync: Flush all disk caches to disk.
#lshw :List all hardware
#lsblk :List information about block devices.
#findmnt: Find a (mounted) filesystem.
#blkid : locate/print block device attributes
#fdisk : Display or manipulate a disk partition table.
#mkfs: Make file filesystem
#mkswap: Make a swap area on a device or in a file
#parted: Disk partitioning and partition resizing program. It allows the user to create, destroy, resize, move and copy ext2, ext3, Linux-swap, FAT and FAT32 partitions.
#sfdisk: List the size of a partition, the partitions on a device, check the partitions on a device, and repartition a device.
#file: Determine type of FILEs
#Backup and #Remote #Storage
#dump: Write a disk partition to a backup medium.
#restore: used for restoring files from a backup created using dump.
#cdrecord: record audio or data CD, DVD or BluRay
#rsync: is a file transfer program capable of efficient remote update via a fast differencing algorithm.
#mt: Control magnetic tape drive operation.
#cpio: copies files to and from archives
#cp/scp : copy/ remote copy files
#dd: in simplest terms copies an image of a selected disk area. Then provides the ability to copy selected blocks of a physical disk.
#tar/zip/gzip : compress files
#Monitoring #Linux system
#ps: List process.
#uptime: View the system load.
#w: List active processes for all users.
#top: Monitor resource-intensive processes interactively.
#htop: utility that allows the user to interactively monitor the system's vital resources or server's processes in real time.
#iotop: display and monitor the disk IO usage details and even gets a table of existing IO utilization by the process
#gnome-system-monitor: Monitor system load and processes graphically.
#xload: Simple, graphical monitor of system load.
#free: Display free memory.
#pidof: Command, which looks up and prints the PID of a process by its name
#nmon: fully interactive performance monitoring command-line utility tool for Linux. It is a benchmark tool that displays performance about the CPU, MEMORY, NETWORK, DISKS, FILE SYSTEM, NFS, TOP PROCESSES, RESOURCES, AND POWER MICRO-PARTITION
#lsof : display a list of all the open files and the processes. The open files included are disk files, network sockets, pipes, devices, and processes.
#iostat: Report Central Processing Unit (CPU) statistics and input/output statistics for devices and partitions.
#Psacct or Acct : monitor user activities
#whowatch – Monitor Linux Users and Processes in Real Time
#vmstat: display statistics of virtual memory, kernel threads, disks, system processes, I/O blocks, interrupts, CPU activity, and much more
#Network Related
#traceroute: View the network path to a remote host.
#ifconfig: Older command to set and display network interface information.
#netstat: list of all active connections.
#who: List logged-in users, long output.
#tcpdump: listing of all active connections.
#ping: Check if a remote host is reachable.
#ifup/ifdown/ifquery: actives/deactivates/query about state of a network interface.
#nslookup: queries Internet name servers interactively for information.
#dig: stands for Domain Information Groper. It is used for retrieving information about DNS name servers.
#mtr: combines the functionality of the traceroute and ping programs in a single network diagnostic tool.
#ip: used for displaying and manipulating routing, network devices, interfaces.
#ethtool: utility for querying and modifying network interface controller parameters and device drivers.
#route: utility for displaying or manipulating the IP routing table of a Linux system.
#nmcli: scriptable command-line tool to report network status, manage network connections, and control the NetworkManager.
#ss: utility to investigate sockets. It dumps socket statistics and displays information similar to netstat.
#nc: also referred to as the “Network Swiss Army knife”, is a powerful utility used for almost any task related to TCP, UDP, or UNIX-domain sockets. It is used to open TCP connections, listen on arbitrary TCP and UDP ports, perform port scanning plus more.
#host: command is a simple utility for carrying out DNS lookups, it translates hostnames to IP addresses and vice versa.
#Instant #Messaging
#write: Send messages to a terminal.
#mesg: Prohibit talk and write.
#tty: Print your terminal device name.
#wall: allow us to send messages to another user in the terminal using tty2
#Web #Browsing
#lynx: open source command line browser
#Links2: text-based browser that you can easily utilize on your terminal with a good user experience.
#elinks: eLinks is similar to Links2 — but it is no longer maintained.
#wget: non-interactive network downloader which is used to download files from the server
#curl: (short for "Client URL") is a command line tool that enables data transfer over various network protocols
#W3M: open-source text-based web browser for the terminal.
#Email:
#mail: mail command is quite popular and is commonly used to send emails from the command line.
#mailx: Mailx is the newer version of mail command and was formerly referred to as nail in other implementations.
#mutt: Mutt is a lightweight Linux command line email client. Unlike the mail command that can do basic stuff, mutt can send file attachments.
#mpack: mpack command is used to encode the file into MIME messages and sends them to one or several recipients, or it can even be used to post to different newsgroups.
#sendmail: a most popular SMTP server used in most of Linux/Unix distribution. Sendmail allows sending email from command line.
#swaks: command is a scriptable, flexible, transaction-oriented SMTP tool.
#ssmtp: send emails using the SMTP server from the Linux terminal.
#Network Connection
#ssh: Securely log into a remote host, or run commands on it.
#telnet: Log into a remote host (insecure!).
#scp: Securely copy files to/from a remote host (batch).
#sftp: Securely copy files to/from a remote host (interactive).
#ftp: Copy files to/from a remote host (interactive, insecure!).
#Host Location
#host: Look up hostnames, IP addresses, and DNS info.
#whois: Look up the registrants of Internet domains.
#ping: Check if a remote host is reachable.
#traceroute: View the network path to a remote host.
#dig: dig is a tool for querying DNS nameservers
#Host Information:
#uname: Print basic system information.
#lshw: extract detailed information on the hardware configuration of the machine
#lscpu: gathers CPU architecture information from sysfs, /proc/cpuinfo and any applicable architecture-specific libraries
#lsblk: lists information about all available or the specified block devices
#lsusb: displaying information about USB buses in the system and the devices connected to them
#lspci: utility for displaying information about PCI buses in the system and devices connected to them
#dmidecode: hardware information by reading data from the DMI tables
#hostname: Print the system’s hostname.
#dnsdomainname: Same as hostname -d.
#domainname: Same as hostname -y.
#nisdomainname: Same as hostname -y.
#ypdomainname: Same as hostname -y.
#ip: Set and display network interface information.
#ifconfig: Older command to set and display network interface information.
#hwinfo is used to probe for the hardware present in the system. It can be used to generate a system overview log which can be later used for support.
#User Management
#useradd: Create an account.
#userdel: Delete an account.
#usermod: Modify an account.
#passwd: Change a password.
#chfn: Change a user’s personal information.
#chsh: Change a user’s shell.
#Group Management
#groups: Print the group membership of a user.
#groupadd: Create a group.
#groupdel: Delete a group.
#groupmod: Modify a group.
#User and Environment:
#logname: Print your login name.
#whoami: Print your current, effective username.
#id: Print the user ID and group membership of a user.
#who: List logged-in users, long output.
#users: List logged-in users, short output.
#finger: Print information about users.
#last: Determine when someone last logged in.
#printenv: Print your environment.
#Login Logout Shutdown Reboot
#shutdown: arranges for the system to be brought down in a safe way,All logged-in users are notified that the system is going down and, within the last five minutes of TIME, new logins are prevented.
#reboot: This will reboot the system immediately
#pm-hibernate/systemctl hibernate: Most of the computer’s hardware is not capable of Hibernation. You can enter the pm-hibernate command and check.
#init 0 : Shutsdown the system
#init 6 : will reboot the system
#systemctl [halt/poweroff/reboot/suspend/hibernate] : uses systemctl command to perform action
#halt/halt -p: command allows you to halt the system, without actually powering down. if we use -p it will power off too
#poweroff: command which allows you to power off the system after shutting down.
#Scheduling jobs in Linux
#sleep: Wait a set number of seconds, doing nothing.
#watch: Run a program at set intervals.
#at: Schedule a job for a single, future time.
#crontab: Schedule jobs for many future times.
#Controlling Process:
#kill: Terminate a process (or send it a signal).
#killall: When started by a root user, the killall command cancels all cancellable processes except those processes that started it
#nice: Invoke a program at a particular priority.
#renice: Change a process’s priority as it runs.
#cpulimit: interrupt execution of a process (or process group) if the CPU/system load goes beyond a defined threshold.
#ulimit: Used to define various limits on files/process/memory etc
