ls:
Lists directories and files in the current directory.
Example:
ubuntu@panda:~$ ls
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pwd:
Prints the current working directory.
Example:
ubuntu@panda:~$ pwd
/home/ubuntu
cd:
Navigate through directories.
Example:
ubuntu@panda:~$ cd clab
ubuntu@panda:~/clab$ cd
ubuntu@panda:~$
mkdir:
Create directories.
Example:
ubuntu@panda:~$ mkdir newdir
ubuntu@panda:~$ ls
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mv:
Move or rename files.
Example:
ubuntu@panda:~$ mv downloads downloads_backup
ubuntu@panda:~$ ls
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cp:
Copy files.
Example:
ubuntu@panda:~$ cp package-lock.json package-lock-backup.json
ubuntu@panda:~$ ls
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rm:
Delete files or directories.
Example:
ubuntu@panda:~$ rm package-lock-backup.json
ubuntu@panda:~$ ls
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touch:
Create blank/empty files.
Example:
ubuntu@panda:~$ touch newfile.txt
ubuntu@panda:~$ ls
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cat:
Display file contents on the terminal.
Example:
ubuntu@panda:~$ cat newfile.txt
hello world
clear:
Clear the terminal display.
Example:
ubuntu@panda:~$ clear
echo:
Print any text that follows the command.
Example:
ubuntu@panda:~$ echo "hello world"
hello world
less:
Display paged outputs in the terminal.
Example:
ubuntu@panda:~$ less package-lock.json
man:
Access manual pages for Linux commands.
Example:
ubuntu@panda:~$ man ls
uname:
Get basic information about the OS.
Example:
ubuntu@panda:~$ uname -a
Linux panda 5.15.0-1049-oracle
whoami:
Get the active username.
Example:
ubuntu@panda:~$ whoami
ubuntu
tar:
Extract and compress files.
Example:
ubuntu@panda:~$ tar -xvf archive.tar
grep:
Search for a string within an output.
Example:
ubuntu@panda:~$ grep "pattern" filename
head:
Return the specified number of lines from the top.
Example:
ubuntu@panda:~$ head -n 5 filename
tail:
Return the specified number of lines from the bottom.
Example:
ubuntu@panda:~$ tail -n 5 filename
diff:
Find the difference between two files.
Example:
ubuntu@panda:~$ diff file1 file2
cmp:
Check if two files are identical.
Example:
ubuntu@panda:~$ cmp file1 file2
comm:
Combine the functionality of diff and cmp.
Example:
ubuntu@panda:~$ comm file1 file2
sort:
Sort the content of a file while outputting.
Example:
ubuntu@panda:~$ sort filename
export:
Export environment variables.
Example:
ubuntu@panda:
ps:
Display active processes.
Example:
ubuntu@panda:~$ ps
PID TTY TIME CMD
1234 pts/1 00:00:01 bash
5678 pts/1 00:00:03 python
kill and killall:
Kill active processes by process ID or name.
Example:
ubuntu@panda:~$ kill 1234
ubuntu@panda:~$ killall python
df:
Display disk filesystem information.
Example:
ubuntu@panda:~$ df -h
Filesystem Size Used Avail Use% Mounted on
/dev/sda1 20G 15G 4.0G 80% /
chmod:
Change file permissions.
Example:
ubuntu@panda:~$ chmod 755 script.sh
ubuntu@panda:~$ ls -l script.sh
-rwxr-xr-x 1 ubuntu ubuntu 0 Jan 1 12:00 script.sh
chown:
Grant ownership of files or folders.
Example:
ubuntu@panda:~$ chown ubuntu:ubuntu script.sh
ubuntu@panda:~$ ls -l script.sh
-rwxr-xr-x 1 ubuntu ubuntu 0 Jan 1 12:00 script.sh
ifconfig:
Display network interfaces and IP addresses.
Example:
ubuntu@panda:~$ ifconfig
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.1.2 netmask 255.255.255.0 broadcast 192.168.1.255
traceroute:
Trace all the network hops to reach the destination.
Example:
ubuntu@panda:~$ traceroute google.com
wget:
Direct download files from the internet.
Example:
ubuntu@panda:~$ wget https://example.com/file.zip
cal:
View a command-line calendar.
Example:
ubuntu@panda:~$ cal
January 2023
Su Mo Tu We Th Fr Sa
1
2 3 4 5 6 7 8
9 10 11 12 13 14 15
16 17 18 19 20 21 22
23 24 25 26 27 28 29
30 31
alias:
Create custom shortcuts for regularly used commands.
Example:
ubuntu@panda:~$ alias ll='ls -l'
ubuntu@panda:~$ ll
total 4
drwxrwxr-x 2 ubuntu ubuntu 4096 Jan 1 12:00 clab
whereis:
Locate the binary, source, and manual pages for a command.
Example:
ubuntu@panda:~$ whereis ls
ls: /bin/ls /usr/share/man/man1/ls.1.gz
whatis:
Find what a command is used for.
Example:
ubuntu@panda:~$ whatis ls
ls (1) - list directory contents
top:
View active processes live with their system usage.
Example:
ubuntu@panda:~$ top
useradd and usermod:
Add new user or change existing users’ data.
Example:
ubuntu@panda:~$ sudo useradd newuser
ubuntu@panda:~$ sudo usermod -aG sudo newuser
passwd:
Create or update passwords for existing users.
Example:
ubuntu@panda:~$ sudo passwd newuser
Enter new UNIX password:
Retype new UNIX password:
passwd: password updated successfully
ls -1 | wc -l:
Get the count of the files present in a directory.
Example:
ubuntu@panda:~$ ls -1 | wc -l
12
kill:
Command to kill a process (PID).
Example:
ubuntu@panda:~$ kill 1234
w:
Check how many users are logged into Linux.
Example:
ubuntu@panda:~$ w
12:00:00 up 10 days, 2:00, 2 users, load average: 0.00, 0.01, 0.05
date:
Used to check the current date and time in Linux.
Example:
ubuntu@panda:~$ date
Sat Jan 1 12:00:00 UTC 2023
ls -a:
List the hidden files in a directory.
Example:
ubuntu@panda:~$ ls -a
. .. .hiddenfile clab downloads
ls -l:
Check the permissions on all the files.
Example:
ubuntu@panda:~$ ls -l
total 4
drwxrwxr-x 2 ubuntu ubuntu 4096 Jan 1 12:00 clab
ls -R:
List information about files and directories within the file system.
Example:
ubuntu@panda:~$ ls -R
.:
clab downloads
./clab:
file1 file2
./downloads:
file3 file4
rm -rf:
Remove directory with the files.
Example:
ubuntu@panda:~$ rm -rf testdir
ubuntu@panda:~$ ls
clab downloads