Basic Linux Commands

Here are a list of basic linux commands

cat filename	write contents of filename to the screen
cd directory_name	change current directory to directory_name
chmod mode file	change permissions on file to mode.
grep phrase filename	search filename for phrase and print matching lines
grep phrase	read from the standard input, and print lines matching phrase
mkdir name	Create a directory with name
man command	Find information about the command in man (help) pages
Info command	Find Information about the command
Who	Displays users who are currently logged in
grep -v phrase	print all lines not matching phrase
Whoami	User running the current terminal
History	Displays already executed commands
History –n	Cleans the history ( removed the already executed commands)
Tty	Shows the terminal type
Su	Switch user ex: su – tom , logs into the tom user account
lpr -Pprinter_name filename	Print the file filename to the printer printer_name
lpq	check the printer queue
lprm job_number	remove the print job numbered job_number from the print queue (to find out what job nuimber your print job is, use lpq.)
tocuh file	Create a file with current time stamp
Cp file location	Copies a specified file to a specified location
Mv file1 file2	Renames a file ,directory or also moves the files to a specified location
Alias	Create a alias to a command ,ex: alias tom=ls , now tom works much like ls command
Cut	Cut contents in file ,ex:cut –d: -f6 file : cuts the sixth field
Less file	Shows files in one screen full
More file	Much like less command
Head	Shows the head contents of the file
Head –n 5	Shows the head 5 line
ls	List files in current directory (not including files that start with a dot.
Tail file	Show the end part of the file
Tail –n 10 file	Shows the last 10 lines in a file
Wc	Provides information about the character count ,line count e.t.c
Locate file	Locate files (much like find command)
Fdisk –l	Shows the disk information
Chsh	Change shell
Users	Print the current user names
Id	Print the current user to whom we logged in
Last	Displays most recent logged in information
Laslog	Displays most recent login information
Free	Displays memory information
Echo “string”	Echos the string sent
Echo –e “string” > file	Writes the string to the file
Cmp	Compare files ex : cmp –l fil11 file2
Diff	Checks 2 files for differences ex:diff –by file1 file2
Cat /proc/version	Basic information about cpu
Uname	Print system information
Echo $PATH	Shows the current Path
Echo $SHELL	Shows the current running shell
Runlevel	Shows the current running run level
Ps	Shows the currently running process
Kill -9 pid	Kills the running process with ID pid
Sysctl	Interface for examining or dynamically changing parameters in linux
ls directory_name	List files in directory_name
ls -l	List files with permissions, ownership and last modified date
ls -a	list all files, including files that start with a dot (like the .netscape directory)
ls -R	list contents recursively, that is , list contents of subdirectories.
pwd	"print working directory", ie says what directory you are in
rm filename	removes filename
rm -f	f is for "force". With this option, files are removed without confirmation.
rm -r directory_name	recursively delete directory_name and its contents.
rmdir directory_name	removes a directory called directory_name. Only works on empty directories. to remove a nonempty directory, see rm -rf
telnet hostname	connect to the machine called hostname
wc filename	print the number of lines, words, and characters in filename. If No filename is given, stdin is used.
Watch	Execute a program periodically
Cron,crontab	Commands for scheduling jobs
Scp	Command for transferring file to remote destination
Unlink	Delete a file ex: unlink filename
Halt,	Halt the system
Poweroff	Halt the system and poweroff
Shutdown	Shutdown
Reboot	Reboot the system
Command	Run a command ex: command ls (runs the ls command)
Dircolrs	See the colors assigned to directories
Dir	Briefly list the directory contents
Dirs	Show remembered directory listing
Logname	Print the login name
Nl	Number of lines in a file ex:nl filename
Type	Describe a command
Ss	Dump socket stastics
Du	Disk usage
Df	File system usage
Iostat	Cpu Statistics Information
Modprobe	Load a module into kernel
Dmidecode –type 6	Ram type
Last reboot	Last reboot information
Shred	Delete files perminantlystrace
Strace	See command executing
Time	Display time
Whereis	To find location of some thing ex:whereis ls (find location of ls command)
Whatis	To get information