Commonly used Linux commands

Linux Command Line Tutorial For Beginners - Copy

Command	Explanation	Example
ls	List files in directory; current directory is used if no directory is supplied	$ ls ~/Desktop
cd	Change the current working directory	$ cd /home/centos/
pwd	Print the current working directory	$ pwd /home/centos/
cp	Copy a file	$ cp orig.txt copy.txt
mv	Move or rename a file	$ mv a.txt Desktop/b.txt
rm	Delete a file	$ rm file.txt
mkdir	Create a directory	$ mkdir examples/
rmdir	Delete a directory (must be empty)	$ rmdir examples/
cat	Print one or more files to STDOUT	$ cat file.txt
grep	Search for text within a file or STDIN	$ grep 10.10.1.1 /var/log/apache/*
file	Identify the file type	$ file image.jpg image.jpg: JPEG Image Data
head	Display the first 10 lines of a file (use “-n X” to display first X lines)	$ head /etc/passwd $ head -n 5 /etc/passwd
tail	Display the last 10 lines of a file (use “-n x” to display first X lines)	$ rm file.txt
tail -F	Display new data as it is appended to the end of a file (useful for watching logs)	$ tail -F /var/log/messages
less	Display text from STDIN or a file one screen at a time	$ less /etc/passwd $ cat file \| less
ps	Display a list of running processes	$ ps aux
lsof	Display a list of open files	$ lsof
netstat	Display TCP & UDP connection info	$ netstat -na
ifconfig	Display information about your network interfaces, such as your IP address	$ ifconfig
su	Temporarily switch to a different user. Root is used if no username is specified	$ su – [username]
sort	Sort the contents of a file or STDIN	$ sort /etc/passwd
uniq	Remove duplicate lines from a sorted file or sorted STDIN	$ uniq mylist.txt
chmod	Change the permissions (mode) of a file or directory	$ chmod +w file.txt
stat	View detailed information about a file	$ stat file.txt
ping	Send ICMP ECHO_REQUEST to a network host to test connectivity	$ ping 10.1.1.1
whoami	Display the current username	$ whoami
passwd	Change a user’s password, or your own if no username is specified	$ passwd [username]
kill	Terminate or send a signal to a running process by process ID(PID)	$ kill 8573
ln	Create a hard or symbolic link to a file	$ ln [file] [link]

Bash Commands
uname -a Show system and kernel
mount Show mounted file system
date show system date
whoami Show your username
man command Show manual for command

Bash Shortcut
Ctrl-c Stop current command
Ctrl-z Sleep Program
Ctrl-a Go to start of line
Ctrl-e Go to end of line
Ctrl-u Cut from start of line
Ctrl-k Cut from end of line

Directory Operations
pwd Show current directory
mkdir dir Make directory dir
cd dir Change directory to dir
cd .. Go up a directry
ls List files

Ls Option
ls -a Show all(include hidden)
ls -R Recursive list
ls -r Reverse order
ls -t Sort by last modified
ls -S Sort by file size
ls -l Long listing format

Bash Variable
env Show environement variable
echo $NAME Output value of $NAME variable
export $NAME= value Set $NAME to value
$PATH Executable search path
$HOME Home directory
$SHELL Current shell

Search File
grep pattern file Search for pattern in file
grep -i Case insensitive search
find /dir -name name Find file starting with name in dir
locate file Find file

File Operation
touch file1 Create file1
cat file1 file2 Concatenate file1 & file2
less file View and paginate file
cp file1 file2 Copy file1 to file2
mv file1 file2 Move file1 to file2
rm file Remove file

File Permission
chmod xxx file Change mod file to xxx
chmd -R xxx folder Recursivly chmod folder to xxx
chown user:group file Change file owner to user and group to group

I/O Redirection
cmd > file Standard output of cmd to file
cmd >> file Append standout to file
cmd 2> file Error output of cmd to file
cmd 1>&2 Stdout to same place as stderr
cmd &> file Every output of cmd to file

Process Managment
ps Show snapshot of processes
top Show real tie processing
kill pid Kill process with pid
killall name Kill all processus with names beginning name