Linux Admin Commands

Linux Admin Commands 

S/N	Command	Description
1	ssh -i ubuntu.pem ubuntu@192.168.20.201	Access via PEM file
2	zip -r httpdocs.zip httpdocs --exclude *.svn* --exclude *.git*	Zip with exclude some files
3	find . -type d -exec chmod 775 {} \;	Apply permission along subfolders excluding files
4	find . -type f -exec chmod 644 {} \;	Apply permission along subfiles excluding folders
5	find . -name \*test.txt -type f -exec rm -f {} \;	Delete all the matching files with the same name
6	find /home -type f -name "*.tar.gz" -exec du -sh {} \;	Find and display size of tar.gz files
7	find . -type f -name "*.zip" -size +1G -exec du -sh {} \;	Find zip files larger than 1GB
8	find . -name "*.tar.gz" -type f -mmin +15 -delete	Delete files older than 15 minutes
9	find /var/log/apache2/ -name "*.gz" -mtime +5 -delete	Delete files older than 5 days
10	find . -exec grep -Rnw 'India' {} \;	Find a specific word in a file
11	scp ubuntu@ip/home/ubuntu/pagal /home/administrator	Drag file from server
12	rsync -avzh --progress (file) ssh ubuntu@ip:/home/ubuntu	Drop file in server
13	rsync -avzh --progress root@127.0.0.1:/root/html.tar.gz .	Drag file from server
14	tar -xvf new.tar -C /home/administrator/Desktop/	Change extract location
15	mysqldump -u root -p database_name > database.sql	MySQL dump
16	mysqldump -u root -p --all-databases > all.sql	Dump all databases
17	mysql -u root -p database_name < database.sql	MySQL restore
18	sudo update-rc.d atd disable	Enable or disable a service in Ubuntu
19	find /home/USERNAME/public_html -type d -exec chmod 755 {} \;	Set permissions for folders/directories
20	find /home/USERNAME/public_html -type f -exec chmod 644 {} \;	Set permissions for files
21	traceroute 31.170.123.130	Check connectivity between source and destination
22	nslookup domain_name or ip_address	Resolve IP to name and name to IP
23	0 9 * * * /usr/bin/find /home/ubuntu/database_backup -name "*.gz" -type f -mtime +10 -exec rm -f {} \;	Delete files older than 10 days
24	telnet (ip_address) (port_no)	Check if a port is open or closed
25	nmap -p port_no 100.100.7.32	Check if a specific port is open
26	nmap -sT 100.100.7.32	Check how many ports are open
27	gnome-open https://google.com	Open a link in the browser
28	ss	Display network socket-related information
29	sudo netstat -tulpn	Show currently running open ports
30	passwd --delete user_name	Delete a user's password
31	sudo ss -lptn 'sport = :5432'	Check all process IDs for a specific port
32	whois IP_address	Show hosting details
33	find $HOME -type d -name ".git"	Find a specific folder path
34	wget https://example.com/db.sql	Download a file from the server
35	sudo service --status-all	Check All service status
36	sed -i -e 's/old-text/new-text/g' input.txt	(g) is used when you want to replace multiple occurrences on the same line.
37	sed -i -e 's/old-text/new-text/' input.txt	If you don't include the g, it will only replace the first occurrence.
38	sed -i '5s/old-text/new-text/' input.txt	Change string with specific line number.
39	sed -i '/host/s/^#//g' input.txt	To Uncomment.
40	sed -i '/2001/s/^/#/g' input.txt	To Comment Out.
41	sudo sed -i '812s/max_file_uploads = 20/max_file_uploads = 200/' php.ini	Update max_file_uploads value in php.ini.
42	grep 'max_file\|memory_limit' php.ini	Grep one or more strings with \| symbol.
43	rm -rf -v !("filename1"|"filename2")	To delete all files with the exception of filename1 and filename2.
44	arp	Get the MAC address list.
45	arp-scan -l	Get the MAC address list with system names like HP.
46	apt list --installed	Check installed packages in Ubuntu.
47	Command in the comment Section, not posted here due to html syntax detaction	Calculate load average.
48	~/.local/share/Trash/files	Terminal Trash location.
49	php --ini	View PHP version and extensions.
50	password --delete user_name	Delete user password.
51	http://tech2towards.tech/?nocache	View site without cache (if existing code loading).
52	dpkg -l | grep mysql	Check installed packages.
53	sudo deluser --remove-home itadministrator	Delete user account with home directory.
54	load_avarage/no_of_cpu*100 (3.56/4*100) = 89%	Calculate load average
55	sudo apt-get install glances	Glances is a monitoring tool similar to TOP
56	dig google.com ANY	dig is similar to nslookup but has advanced features
57	http://server_ip/~cpaneluser	Open website without a domain name in a shared hosting server
58	sudo chmod --reference ram syam	Apply the same permission of ram to the syam folder (applies only to directories, not recursively)
59	sudo chown --reference ram syam	Change ownership of syam to match ram
60	apg -n 1 -MCLN -m 16 -s	Generate a secure password using this command
61	dpkg -l *python2.7*	Check installed software matching Python 2.7
62	umask	Set default permissions for all files/directories
63	chattr +i file.txt	Prevent even root user from deleting the file (+ for apply, - for remove)
64	lsattr file.txt	Check if chattr is applied
65	grep -i -r "server_name" /etc/nginx/sites-available/	Search case-insensitively (-i) and recursively (-r)
66	/usr/sbin/mysqld --help --verbose	View all MySQL details
67	https://www.sslforfree.com/	Install SSL in WHM/Cpanel for Linux or Windows
68	kill -9 PID	Kill a process by PID
69	killall firefox	Kill a process by name
70	ping www.google.com | while read pong; do echo "$(date): $pong"; done	Ping with date and time
71	ping www.google.com | ts	Ping with date and time (requires sudo apt install moreutils)
72	dig +short demo.example.com	If you receive the CNAME value, it means the CNAME is updated
73	stress --cpu 8 --io 4 --vm 4 --vm-bytes 512M --timeout 10s	Testing load on CPU and RAM
74	gzip -d linux.gz	Extract .gz file in Linux
75	unzip linux.zip	Extract file through unzip
76	/etc/apt/sources.list.d	Remove unwanted source list
77	mkdir -p a/b/c/d/e/f	Create multiple directories with an absolute path
78	mkdir -p a/b/c/d/e/f/{subhash,sachin}	Create multiple directories in the same path
79	ls -R Folder	View all content under "Folder" directory recursively
80	:%s/map/gap	Replace string in vim editor
81	:%s/\$/#/g	Replace special character like $ using "\
82	shutdown -r -f -t 00	Forcefully restart Windows (write in RUN)
83	shutdown -s -f -t 00	Forcefully shut down Windows (write in RUN)
84	appwiz.cpl	Open Programs and Features on Windows
85	ncpa.cpl	Open Network Connections on Windows
86	msconfig	Access Windows 7 startup settings
87	dpkg --status apache2	View detailed info about the installed Apache2 package
88	last reboot	See the last reboot log details
89	whereis openssl	Locate the OpenSSL installation path
90	iotop, iostat, atop	Show advanced process details
91	echo 'HISTTIMEFORMAT="%F %T "' >> ~/.bashrc	Show history with date and time
92	sed 's/unix/linux/g' demofile.txt	Replace a word in a file
93	du -sh .[^.]*	Show all hidden files
94	ps -eo pmem,pcpu,pid,user,args | sort -k 1 -r | head -10	Find out which process is consuming the most CPU and RAM
95	export PS1="\u$"	Make the terminal host display shorter
96	sudo sh -c 'apt update && apt install vim'	Install multiple services with a single command
97	pkill -u user_name	Kill all processes running under a specific user
98	who and w	Show information about users currently logged in and their processes
99	pkill -9 -t pts/5	Kill remotely connected user terminal access (after using the w command)
100	cat /sys/block/sda/queue/rotational	1 for hard disks, 0 for SSDs
101	sudo apt-get install trash-cli	Install Trash CLI with commands like trash-list and trash-restore
102	grep -Rnw '/home/ubuntu/Desktop' -e 'India'	Find a specific word in files
103	grep --exclude=*.csv -Rnw '/home/ubuntu/Desktop' -e 'India'	Exclude files while searching for a specific word
104	ssh root@10.10.3.4 'uptime'	Execute commands without logging into the terminal
105	locate -b apple.txt	Use locate as a reliable and better alternative to the find command
106	sudo adduser user_name sudo	Make a user an administrator in Ubuntu via CLI
107	cat /etc/resolv.conf	Check name server configuration in Linux
108	nmtui/nmcli connection show	Configure IP addresses via CMD
109	runuser -l User-Name -c 'command'	Run a command as a specific user
110	csf -g | grep 8000	Check port input/output rules in WHM
111	for user in $(getent passwd | cut -f1 -d: ); do echo $user; crontab -u $user -l; done	Get all cron jobs for all users on the server
112	touch /home/ubuntu/demofile:`date '+%d-%m-%y_%H:%M:%S'`	Create a file with the current date and time
113	sudo apt-get install lamp-server^ -y	Install Lamp Server
114	find /etc -xdev -type f -printf '\n' | wc -l	Count all the files in the directory
115	mtr -r -c 100 125.63.73.83	MTR is a network diagnostic tool combining traceroute and ping functionality
116	./nikto.pl -h https://tech2towards.com/	Nikto web server scanner
117	dig +short myip.opendns.com @resolver1.opendns.com	Get public IP address via Linux CLI
118	mysqladmin -u root -p status	Get MySQL status, including slow queries
119	* * * * * /usr/bin/bash /home/sh.sh >> /var/log/script.log 2>&1	Save script logs to a specific file
120	curl http://checkip.amazonaws.com/	Get public IP address
121	curl -ISL https://example.com/	Get link information, including server type
122	figlet	Create ASCII art from text
123	https://example.com/?nocache=12345	Open URL without cache (replace "12345" with a random string)
124	du -sh .??*	Display the total size of all hidden directories
125	sudo apt-cache depends nginx	Check package dependencies
126	SOURCE /path/to/your/file.sql;	Import a MySQL SQL file from within MySQL