Linux Commands

Device Management
Ctrl + shift + “+”	Zoom IN
Ctrl + “-”	Zoom out
sudo su	super user do, can loggin as root user
who	User logged in
whoami	Current user logged in
man	Manual pages info
who -b	last system boot time and date
cal, cal -1, cal -3	calendar
clear	clears the screen
File System Management
pwd	Present working directory
cd bin	Change directory
cd ..	go to previous directory
cd ../..	go back to 2nd previous directory
cd ~	shows default location, ~ tilt
cd -	shows current location
ls	List file and directory available at current location
ls -F	list symbolic files and directories
ls -l	list file info in long listing format, display will be following total 5 – total 5 bock assigned -   >file type (normal file) rw-rw-r--    >file permission 1   >number of linked files rahul    >file owner rahul    >file group 21     >file bytes size Aug    >month of file creation 30     >date 12:09    >time rahul   >file name
ls –t	display time based assigning order files, latest file first display
ls -1	every line 1 and 1 file will be displayed
ls -s	size of block per file
ls -S	big size file will be displayed first, descending order
ls -i	display files with inode number, file index number at location
ls R*	list file name beginning with letter R
ls -a	show hidden file/directory as well, “.” Will show system defined/related hidden CURRENT directories information,  “. .” parent directory
ls ?	display only single character file
ls ??	two character file
ls [abcd]*	display any/all file names starting with either a,b,c or d
ls [a-d]*	list files names starting with either a,b,c or d
cat > .rahul	“.” Means create user defined hidden file
cat .rahul	open hidden file name rahul
cat > rahul	create rahul file with ASCII text input, ctrl + d to save and exit
cat < Rahul	display file Rahul, input redirectional operator
cat >>	append lines to a file, append redirectional operator
cat ?	display content of single character file
touch file1 file2	multiple empty files creation
touch –a file1	change only the access time
touch –d ‘ date month year time’ file1	change last modification time
stat file1	status of file ,access, modify , change details of file1
touch –m file1	change only the modification time
file *	shows file details, empty files
mkdir .dir3	create hidden directory name dir3
mkdir dir1 dir2	empty directories create
rm dir1 dir2 or rmdir dir1	remove only empty directories/files
rm –v file1	will give file removed message, -v verbose “explain ” what is being done by the command
rm –R dir1	can remove non empty directories and file structures
rm ??	files with two character names will be removed
rm [abcd]*	remove files any/all file names starting with either a,b,c or d
rmdir ?	single character named directories will be removed
rmdir *	remove all empty directory from current directory
cp and mv	cp means copy paste and mv means cut paste
mv Linux Unix	rename source file Linux with name Unix
mv .shell shell	hidden file .shell is converted to read file name shell
mv rahul1 rahul2 RAHULKAUL /RAHUL/	cut paste files rahul1,rahul2 and RAHULKAUL from present directory to /RAHUL/ directory
cp shell pearl	copy shell file content to same location with file name as pearl
cp –R	used for coping directories
?	Meta-characters >> special characters perform certain operations in simple way >> wildcard matches single character at a time
*	asteric > matches single or more character at a time
[ ]	matches any character in list
-	range, from to to

File Permissions
ls -l	-rw-rw-r-- -     Type of the file rw-  owner/user rw-  group r--    others
	r-  read w- write -   no permission x-  execute
	user+group+others=all   >a
$ chmod	change mode