Most Frequently Used Linux Commands

In this article we give you the most as often as possible used Linux Commands. Coming from the solace of a PC or Mac work area, the Linux Command Line looks not at all like what you regularly utilize.

For somebody to work in the Terminal they have to acquaint themselves with Linux commands. The Linux Command line is very helpful, fundamental to utilizing your Linux or VM and if done right, it furnishes you with more understanding and handy use than the Windows or Mac work area ever could.

System Linux Commands

Command	Uses
uname	Displays linux system information
cat /etc/redhat_release	Displays which version of redhat installed
uptime	Display how long the system has been running
hostname	Display system host name
last reboot	Display system reboot history
date	Display the current date and time
cal	Display the calendar of the current month
w	Displays who is logged on
whoami	Displays current user id
finger user	Displays information about user
reboot	Reboots the system
shutdown	Shuts down the system

Hardware Linux Commands

Command	Uses
dmesg	Displays all the messages from Kernel ring buffer
cat /proc/cpuinfo	Displays information about processes and CPUs of the system
cat /proc/meminfo	Displays details on hardware memory
cat /proc/interrupts	Lists the number of interrupts per CPU per I/O device
lshw	Displays information on hardware configuration of the system
lsblk	Displays block device related information of the machine
free -m	Display used and free memory
dmidecode	Displays hardware info from the BIOS
hdparm -i /dev/sda	Displays info about disk sda
hdparm -tT /dev/sda	Performs a read speed test on disk sda
badblocks -s /dev/sda	Tests for unreadable blocks on disk sda
lspci -tv	Display information on PCI buses devices

File Linux Commands

Command	Uses
ls -al	Displays all information about files/directories.
pwd	Shows current directory path
mkdir directory-name	Creates a directory
cp file1 file2	Copies linux files, here file1 to file2
cp -r dir1 dir2	Copies dir1 to dir2, creates dir2 if it doesn’t exist
mv file1 file2	Moves files from one place to another/renames file1 to file2
rm file-name	Deletes file
rm -r directory-name	Deletes directory recursively
rm -f file-name	Forcefully removes file
rm -rf directory-name	Forcefully removes directory recursively
ln -s /path/to/file-name link-name	Creates a symbolic link to file-name
tail -f file	Outputs the contents of file as it grows starting with the last 10 lines
gpg -c file	Encrypts file
gpg file.gpg	Decrypts file
cksum file	View the checksum of the file
diff file1 file2	View the differences between contents of file1 and file2
ln -s link file	Create a soft link named link to the file
sort	Sorts files in alphabetical order
touch file	Creates empty file
cat file	Prints the file content in terminal
more file	Display the contents of file
head file	Display the first 10 lines of file
tail file	Outputs the last 10 lines of file
uniq	Compares adjacent lines in a file and removes/reports any duplicate lines
wc	Counts number of words/lines
dir	Lists the content of the directory
tee	Command for chaining and redirection
tr	Command for translating characters

File Permission & Network Linux Commands

Command	Uses
chmod octal file-name	Changes the permissions of file to octal
chmod 777 /data/test.c	Sets rwx permission for owner , group and others
chmod 755 /data/test.c	Sets rwx permission for owner and rx for group and others
chown owner-user file	Changes owner of the file
chown owner-user:owner-group file-name	Changes owner and group owner of the file
chown owner-user:owner-group directory	Changes owner and group owner of the directory
chgrp group1 file	Changes the group ownership of the file to group1
ifconfig -a	Displays all network interface and set ip address
ifconfig eth0	Displays eth0 ethernet port ip address and details
ip addr show	Display all network interfaces and ip addresses
ip address add 192.168.0.1 dev eth0	78. ip address add 192.168.0.1 dev eth0 : Sets ip address of eth0 device
ethtool eth0	Linux tool to show ethernet status
mii-tool eth0	Linux tool to show eth0 status
ping host	Sends echo requests to the host to test ipv4 connection
whois domain	Gets who is information for domain
dig domain	Gets DNS nameserver information for domain
dig -x hos	Reverse lookup host
host google.com	Lookup DNS ip address for the name
hostname -i	Lookup local ip address
wget file	Downloads file
netstat -tupl	Lists all active listening ports
nslookup	Resolves domain names to IP addresses

Package Installation & Search Linux Commands

Command	Uses
rpm -i pkgname.rpm	Installs rpm based package
rpm -e pkgname	Removes package
make	Install from source file
grep pattern files	Searches for pattern in files
grep -r pattern dir	Searches recursively for pattern in dir
locate file	Finds all instances of file
find /home/tom -name ‘index*’	Finds file names that start with “index” inside /home/tom directory
find /home -size +10000k	Finds files larger than 10000k in /home

Login, File Transfer & Disk Usage Commands

Command	Uses
ssh user@host	Securely connect to a host as user
ssh -p port $ user@host	Connects to host using specific port
telnet host	Connects to the system using telnet port
scp file.txt server2:/tmp	Secure copy file.txt to remote host /tmp folder
scp user@server2:/www/*.html /www/tmp	Copies *.html files from remote host to current host /www/tmp folder
scp -r user@server2:/www /www/tmp	Copies all files and folders recursively from remote server to the current system /www/tmp folder
rsync -a /home/apps /backup/	Synchronizes source to destination
rsync -avz /home/apps $ linoxide@192.X.X.X:/backup	Synchronize files/directories between the local and remote system with compression enabled
df -h	Displays free space on mounted filesystems
df -i	Displays free inodes on mounted filesystems
fdisk -l	Displays disks partitions sizes and types
du -ah	Displays disk usage in human readable form
du -sh	Displays total disk usage on the current directory
findmnt	Displays target mount point for all filesystems
mount device-path mount-point	Mounts a device to the device-path

Reference : Internet