Linux Commands List
Hardware Information
Show bootup messages:
dmesg
See CPU information:
cat /proc/cpuinfo
Display free and used memory with:
free -h
List hardware configuration information:
lshw
See information about block devices:
lsblk
Show PCI devices in a tree-like diagram:
lspci -tv
Display USB devices in a tree-like diagram:
lsusb -tv
Show hardware information from the BIOS:
dmidecode
Display disk data information:
hdparm -i /dev/disk
Conduct a read-speed test on device/disk:
hdparm -tT /dev/[device]
Test for unreadable blocks on device/disk:
badblocks -s /dev/[device]
Run a disk check on an unmounted disk or partition:
fsck [disk-or-partition-location]
Searching
Search for a specific pattern in a file with [grep]:
grep [pattern] [file_name]
Recursively search for a pattern in a directory:
grep -r [pattern] [directory_name]
Find all files and directories related to a particular name:
locate [name]
List names that begin with a specified character [a] in a specified location [/folder/location] by using the find command:
find [/folder/location] -name [a]
See files larger than a specified size [+100M] in a folder:
find [/folder/location] -size [+100M]
File Commands
List files in the directory:
ls
List all files shows hidden files:
ls -a
Show directory you are currently working in:
pwd
Create a new directory:
mkdir [directory]
Remove a file:
rm [file_name]
Remove a directory recursively:
rm -r [directory_name]
Recursively remove a directory without requiring confirmation:
rm -rf [directory_name]
Copy the contents of one file to another file:
cp [file_name1] [file_name2]
Recursively copy the contents of one file to a second file:
cp -r [directory_name1] [directory_name2]
Rename [file_name1] to [file_name2] with the command:
mv [file_name1] [file_name2]
Create a symbolic link to a file:
ln -s /path/to/[file_name] [link_name]
Create a new file using touch:
touch [file_name]
Show the contents of a file:
more [file_name]
or use the cat command:
cat [file_name]
Append file contents to another file:
cat [file_name1] >> [file_name2]
Display the first 10 lines of a file with head command:
head [file_name]
Show the last 10 lines of a file:
tail [file_name]
Encrypt a file:
gpg -c [file_name]
Decrypt a file:
gpg [file_name.gpg]
Show the number of words, lines, and bytes in a file using wc:
wc
List number of lines/words/characters in each file in a directory with the xargs command:
ls | xargs wc
Cut a section of a file and print the result to standard output:
cut -d[delimiter] [filename]
Cut a section of piped data and print the result to standard output:
[data] | cut -d[delimiter]
Print all lines matching a pattern in a file:
awk '[pattern] {print $0}' [filename]
Overwrite a file to prevent its recovery, then delete it:
shred -u [filename]
Compare two files nd display differences:
diff [file1] [file2]
Read and execute the file content in the current shell:
source [filename]
Sort file contents and print the result in standard output:
sort [options] filename
Store the command output in a file and skip the terminal output:
[command] | tee [filename] >/dev/null
Directory Navigation
Move up one level in the directory tree structure:
cd ..
Change directory to $HOME:
cd
Change location to a specified directory:
cd /chosen/directory
File Compression
Archive an existing file:
tar cf [compressed_file.tar] [file_name]
Extract an archived file:
tar xf [compressed_file.tar]
Create a gzip compressed tar file by running:
tar czf [compressed_file.tar.gz]
Compress a file with the .gz extension:
gzip [file_name]
File Transfer
Copy a file to a server directory securely using the Linux scp command:
scp [file_name.txt] [server/tmp]
Synchronize the contents of a directory with a backup directory using the rsync command:
rsync -a [/your/directory] [/backup/]
Users and Groups
See details about the active users:
id
Show last system logins:
last
Display who is currently logged into the system with the who command:
who
Show which users are logged in and their activity:
w
Add a new group by typing:
groupadd [group_name]
Add a new user:
adduser [user_name]
Add a user to a group:
usermod -aG [group_name] [user_name]
Temporarily elevate user privileges to superuser or root using the sudo command:
sudo [command_to_be_executed_as_superuser]
Delete a user:
userdel [user_name]
Modify user information with:
usermod
Change directory group:
chgrp [group-name] [directory-name]
Package Installation
List all installed packages with yum:
yum list installed
Find a package by a related keyword:
yum search [keyword]
Show package information and summary:
yum info [package_name]
Install a package using the YUM package manager:
yum install [package_name.rpm]
Install a package using the DNF package manager:
dnf install [package_name.rpm]
Install a package using the APT package manager:
apt install [package_name]
Install an .rpm package from a local file:
rpm -i [package_name.rpm]
Remove an .rpm package:
rpm -e [package_name.rpm]
Install software from source code:
tar zxvf [source_code.tar.gz]
cd [source_code]
./configure
make
make install
See a snapshot of active processes:
ps
Show processes in a tree-like diagram:
pstree
Display a memory usage map of processes:
pmap
See all running processes:
top
Terminate a Linux processunder a given ID:
kill [process_id]
Terminate a process under a specific name:
pkill [proc_name]
Terminate all processes labelled “proc”:
killall [proc_name]
List and resume stopped jobs in the background:
bg
Bring the most recently suspended job to the foreground:
fg
Bring a particular job to the foreground:
fg [job]
List files opened by running processes with lsof command:
lsof
Catch a system error signal in a shell script:
trap "[commands-to-execute-on-trapping]" [signal]
Pause terminal or a Bash script until a running process is completed:
wait
Run a Linux process in the background:
nohup [command] &
System Management and Information
Show system information:
uname -r
See kernel release information:
uname -a
Display how long the system has been running, including load average:
uptime
See system hostname:
hostname
Show the IP address of the system:
hostname -i
List system reboot history:
last reboot
See current time and date:
date
Query and change the system clock with:
timedatectl
Show current calendar (month and day):
cal
List logged in users:
w
See which user you are using:
whoami
Show information about a particular user:
finger [username]
View or limit system resource amounts:
ulimit [flags] [limit]
Schedule a system shutdown:
shutdown [hh:mm]
Shut Down the system immediately:
shutdown now
Add a new kernel module:
modprobe [module-name]
Disk Usage
You can use the df and du commands to check disk space in Linux.
See free and used space on mounted systems:
df -h
Show free inodes on mounted filesystems:
df -i
Display disk partitions, sizes, and types with the command:
fdisk -l
See disk usage for all files and directory:
du -ah
Show disk usage of the directory you are currently in:
du -sh
Display target mount point for all filesystem:
findmnt
Mount a device:
mount [device_path] [mount_point]
SSH Login
Connect to host as user:
ssh user@host
Securely connect to host via SSH default port 22:
ssh host
Connect to host using a particular port:
ssh -p [port] user@host
Connect to host via telnet default port 23:
telnet host
File Permission
Chown command in Linux changes file and directory ownership.
Assign read, write, and execute permission to everyone:
chmod 777 [file_name]
Give read, write, and execute permission to owner, and read and execute permission to group and others:
chmod 755 [file_name]
Assign full permission to owner, and read and write permission to group and others:
chmod 766 [file_name]
Change the ownership of a file:
chown [user] [file_name]
Change the owner and group ownership of a file:
chown [user]:[group] [file_name]
Network
List IP addresses and network interfaces:
ip addr show
Assign an IP address to interface eth0:
ip address add [IP_address]
Display IP addresses of all network interfaces with:
ifconfig
See active (listening) ports with the netstat command:
netstat -pnltu
Show tcp and udp ports and their programs:
netstat -nutlp
Display more information about a domain:
whois [domain]
Show DNS information about a domain using the dig command:
dig [domain]
Do a reverse lookup on domain:
dig -x host
Do reverse lookup of an IP address:
dig -x [ip_address]
Perform an IP lookup for a domain:
host [domain]
Show the local IP address:
hostname -I
Download a file from a domain using the wget command:
wget [file_name]
Receive information about an internet domain:
nslookup [domain-name]
Save a remote file to your system using the filename that corresponds to the filename on the server:
curl -O [file-url]
Variables
Assign an integer value to a variable:
let "[variable]=[value]"
Export a Bash variable:
export [variable-name]
Declare a Bash variable:
declare [variable-name]= "[value]"
List the names of all the shell variables and functions:
set
Display the value of a variable:
echo $[variable-name]
Shell Command Management
Create an alias for a command:
alias [alias-name]='[command]'
Set a custom interval to run a user-defined command:
watch -n [interval-in-seconds] [command]
Postpone the execution of a command:
sleep [time-interval] && [command]
Create a job to be executed at a certain time (Ctrl+D to exit prompt after you type in the command):
at [hh:mm]
Display a built-in manual for a command:
man [command]
Print the history of the commands you used in the terminal:
history
Linux Keyboard Shortcuts
Kill process running in the terminal:
Ctrl + C
Stop current process:
Ctrl + Z
The process can be resumed in the foreground with fg or in the background with bg.
Cut one word before the cursor and add it to clipboard:
Ctrl + W
Cut part of the line before the cursor and add it to clipboard:
Ctrl + U
Cut part of the line after the cursor and add it to clipboard:
Ctrl + K
Paste from clipboard:
Ctrl + Y
Recall last command that matches the provided characters:
Ctrl + R
Run the previously recalled command:
Ctrl + O
Exit command history without running a command:
Ctrl + G
Run the last command again:
!!
Log out of current session:
exit