Linux Commands cheat sheet – Most popular Linux Commands

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Linux commands cheat sheet
Linux commands cheat sheet

In this tutorial, you will learn most important commands for Linux Command Line. The command line is one of the most powerful features of Linux. There exists a sea of Linux command line tools, allowing you to do almost everything you can think of doing on your Linux PC.

Let’s learn the Linux commands

HARDWARE
dmesg Detected hardware and boot messages
cat /proc/cpuinfo CPU  model
cat /proc/meminfo Hardware memory
cat /proc/interruptS Lists the number of interrupts per CPU per I/O device
Ishw Displays information on hardware configuration of the system
Isbik Displays block device related information  in  Linux
free -m Used and free memory (-m for MB)
Ispci -tv Show PCI devices
Isusb -tv
dmidecode
Show USB devices
dmidecode Show hardware info from the BIOS
hdparm -i /dev/sda Show info about disk sda
hdparm -tT /dev/sda Do a read speed test on disk sda
badblocks -s /dev/sda Test for unreadable blocks on disk sda
SYSTEM
uname -a Display Linux System Information
uname -r Display Kernel release Information
uptime Show how long the system has been running + load
hostname Show system host name
hostname -i Display the IP address of the host
last reboot Show system reboot history show the current date and time
date Show the current date and time
cal Show this month calendar
w Display who is online
whoami who you are logged in as
finger user Display information about user
USERS
id Show the active user id with login and group
last Show last logins on the system
who Show who is logged on the system
groupadd admin Add group “admin”
useradd -c “Sam Tomshi” g admin -m sam #Create user “sam”
userdel sam Delete user sam
adduser sam Add user “sam”
usermod Modify user information
FILE COMMANDS
Is -al Display all information about files/ directories
pwd Show the path of current directory
mkdir directory-name Create a directory
rm file-name Delete file
rm -r directory-nam
rm -f file-name
Delete directory recursively
rm -f directory-nam Forcefully remove file
rm -rf directory-name Forcefully remove directory recursively
cp file1  file2 Copy file1 to file2
cp -r dir1  dir2 Copy dir1  to dir2, create dir2 if it doesn’t exist
mv file1 file2 Rename source to dest / move source to directory
In -s /path/to/file-name link-name #Create symbolic link to file-name
touch file Create or update file
cat > file Place standard input into file
more file Output contents of file
head file Output first 10 lines of file
tail file Output last 10 lines of file
tail -f file C7 contents of file as it grows starting with the last 10 lines
gpg -c file Encrypt file
gpg file.gpg
wc
Decrypt file
wc print the number of bytes, words, and lines in files
xargs Execute command lines from standard input
PROCESS RELATED
ps Display your currently active processes
ps aux I grep ‘telnet’ Find all process id related to telnet process
pmap Memory map of process
top Display all running processes
kill pid Kill process with mentioned pid id
killall proc Kill all processes named proc
pkill process-name Send signal to a process with its name
bg Resumes suspended jobs without bringing them to foreground
fg Brings the most recent job to foreground
fg n Brings job n to the foreground
FILE PERMISSION RELATED
chmod octal file-name Change the permission of the file to octal
Example
chmod 777 /data/test.c Set rwx permission for owner,group,world
chmod 777 /data/test.c Set rwx permission for owner,rx for group and world
chown owner-user file Change owner of the file
chown owner-user:owner-group file-name Change owner and group owner of the file
chown owner-user:owner-group directory Change owner and group owner of the directory
NETWORK
ip addr show Display all network interfaces and ip address (a iproute 2 command,powerful than ifconfig)
ip address add 192.168.0.1 dev ethO Set ip address
ethtool ethO Linux tool to show ethernet status
mii-tool ethO Linux tool to show ethernet status
ping host Send echo request to test connection
whois domain Get who is information for domain
dig domain Get DNS information for domain
dig -X host Reverse lookup host
host google.com Lookup DNS ip address for the name
hostname -i Lookup local ip address
wget file Download file
netstat -tupl Listing all active listening ports
COMPRESSION / ARCHIVES
tar cf home.tar home Create tar named home.tar containing home/
tar xf file.tar Extract the files from file.tar
tar czf file.tar.gz files Create a tar with gzip compression
gzip file Compress file and renames it to file.gz
INSTALL PACKAGE
rpm -i pkgname.rpm lnstall rpm based package
rpm -e pkgname  Remove package
INSTALL FROM SOURCE
./configure
make
make install
SEARCH
grep pattern files Search for pattern in files
grep -r pattern dir search recursively for pattern in dir
locate file Find all instances of file
find /home/tom -name ‘index*’ Find files names that start with “index”
find /home -size +10000k Find files larger than 10000k in /home
LOGIN (SSH AND TELNET)
ssh [email protected] Connect to host as user
ssh -p port [email protected] Connect to host using specific port
telnet host Connect to the system using telnet port
FILE TRANSFER
scp
scp file.txt server2:/tmp
rsync
Secure copy file.txt to remote host /tmp folder
rsync
rsync -a /home/apps /backup/ Synchronize source to destination
DISK USAGE
df-h Show free space on mounted filesystems
df-i Show free inodes on mounted filesystems
fdisk -I Show disks partitions sizes and types
du -ah Display disk usage in human readable form
du-sh Display total disk usage on the current directory
findmnt Displays target mount point for all filesystem
mount device-path mount-point Mount a device
DIRECTORY TRAVERSE
cd.. To go up one level of the directory tree
cd Go to $HOME directory
cd /test Change to /test directory

Very useful Tutorials click here.