linux commands for system admin
1) Access via pem file
ssh -i ubuntu.pem ubuntu@192.168.20.201
2) Zip with exclude some file
zip -r httpdocs.zip httpdocs --exclude *.svn* --exclude *.git*
3) Apply permission along subfolder exclude files
find permission-test/ -type d -exec chmod 700 {} \;
4) Apply permission along files exclude folder
find ! -type d -exec chmod 700 {} \;
find . -name \*test.txt -type f -exec rm -f {} \; -----> Delete all the matching file's with the same name
find /home -type f -name "*.tar.gz" -exec du -sh {} \;
find . -type f -name "*.zip" -size +1G -exec du -sh {} \;
find . -name "*.tar.gz" -type f -mmin +15 -delete -----> Delete files older than 15 min
find /var/log/apache2/ -name "*.gz" -mtime +5 -delete -----> Delete files older than 5 days
find . -exec grep -Rnw 'India' {} \; ------> Find a Specific Word in a File
5) Drag file from server
scp ubuntu@ip/home/ubuntu/pagal /home/adminstrator
6) Drop & Drag file in server
rsync -avzh --progress (file-name) ssh ubuntu@ip:/home/ubuntu ----> Drop file in server
rsync -avzh --progress root@127.0.0.1:/root/html.tar.gz . ----> Drag file from server
7) Change xtaract location
tar -xvf new.tar -C /home/administrator/Desktop/
8) Mysql dump
mysqdump -u root -p database_name > database.sql -------> For Single DB
mysqldump -u root -p --all-databases > alldb.sql ------> For All DB
9) mysql dump restore
mysql -u root -p database_name < database.sql
10) Enable and disable any service in ubuntu
sudo update-rc.d atd disable
11) For directoy
find /home/USERNAME/public_html -type d -exec chmod 755 {} \;
12) For files
find /home/USERNAME/public_html -type f -exec chmod 644 {} \;
13) check connectivity source to destination
traceroute 31.170.123.130
14) resolve ip to name and name to ip
nslookup domain_name or ip_address
15) delete 10 days older data
0 9 * * * /usr/bin/find /home/ubuntu/database_backup -name "*.gz" -type f -mtime +10 -exec rm -f {} \;
- If telnet showing connected that mean port opened/enabled
- If telnet showing Trying that mean port closed/disabled
$ telnet ip-address port-number
nmap -p 22 100.100.7.32 ------------> same work as telnet
nmap -sT 100.100.7.32 ------------> Check how many port open
17) Automatically open selected link in browser
gnome-open https://tech2towards.blogspot.com
18) ss command is a tool that is used for displaying network socket related information
$ ss
19) show running time open ports
sudo netstat -tulpn
20) Check all the process id via mentioned port no of postgres
sudo ss -lptn 'sport = :5432'
21) Show hosting deatils
whois IP_address/Domain_name
22) How to find perticular folder path
find $HOME -type d -name ".git"
23) download file form server "file should be under Document root of webserver"
wget https://tech2towards.com/mysqldump.sql
24) Check All service status
sudo service --status-all
25) Replace the words from abc to XYZ in file via terminal
sed -i -e 's/abc/XYZ/g' test.txt
26) change string with specific line number
sed -i '5s/Best/Next/' demo-file.txt
sudo sed -i '812s/max_file_uploads = 20/max_file_uploads = 200/' php.ini
sed -i '/host/s/^#//g' input.txt -----------> To Uncomment
sed -i '/2001/s/^/#/g' input.txt -----------> To Comment Out
27) delete user password
password --delete user_name_1
28) grep one and more string with \| symbol
grep 'max_file\|memory_limit' php.ini
29) To delete all files with the exception of filename1 and filename2:
rm -rf -v !("filename1"|"filename2")
30) Get the mac addrss list
arp
Get the mac addrss list with system name like hp
arp-scan -l
31) Check installed package in ubuntu
apt list --installed
32) Calculate loadavarage
grep 'cpu ' /proc/stat | awk '{usage=100-($5*100)/($2+$3+$4+$5+$6+$7+$8)} END {print usage}'
33) Termial Trash Location
~/.local/share/Trash/files
34) View PHP version and extionson
php --ini
35) Delete user password
password --delete user_name
36) View site without cache (if existing code loading)
http://tech2towards.tech/?nocache
37) Check installed packages in ubuntu
dpkg -l | grep mysql
38) Delete user account with home directory
sudo deluser --remove-home itadministrator
39) Calculate load avarage by Command.
cat /proc/loadavg | cut -c 1-4 | echo "scale=2; ($(</dev/stdin)/`nproc`)*100" | bc -l
40) Calculate load avarage by calculating.
load_avarage/no_of_cpu*100 (3.56/4*100) = 89%
41) Glances is a monitoring tool as similar as TOP
glances
42) Dig is similar to nslookup, but dig has advance feature
dig tech2towards.tech
dig tech2towards.tech ANY
43) Open website without domain name in shared hosting server
http://server_ip/~cpaneluser
Basically, the website can be checked using the temporary URL (http://server_ip/~cpanelusername/) on cPanel before switching DNS. But for security reason, many hosting providers don’t allow to access the website via server IP address or temporary URL.
Due to this, mod_userdir is disabled and you don’t have permission to enable it on your shared hosting. However, there has another option to test your website before pointing domain name or update DNS records with the new server.
44) Apply same permission of older directory to New directory
sudo chmod --reference Older_directory New_directory
45) Apply same permission of older directory to New directory
sudo chown --reference Older_directory New_directory
46) Generate password via this command
apg -n 1 -MCLN -m 16 -s
47) Check installed software
dpkg -l *python2.7*
48) User for set default permission for all file/directory
umask
49) Root user also not delete this file (+ for apply and - for remove)
chattr +i file.txt
check chattr applied or not
lsattr file.txt
50) (-i use for casesenitive) (-r use for recursive)
grep -i -r "server_name" /etc/nginx/sites-available/
51) View all deatils
/usr/sbin/mysqld --help --verbose
52) kill service by PID
kill -9 PID
53) Kill service by Process name
killall firefox
54) Testing load on CPU and RAM
stress --cpu 8 --io 4 --vm 4 --vm-bytes 512M --timeout 10s
55) Extract .gz file in linux
gzip -d linux.gz
56) Compress through zip extention
zip -r linux.zip linux
Extract file through unzip
unzip linux.zip
57) Create multiple directory with absolute
mkdir -p a/b/c/d/e/f
create multiple directory in same path
mkdir -p a/b/c/d/e/f/{subhash,sachin}
58) view all content under "Folder" directory with recursive
ls -R Folder
59) replace word in vim editor
:%s/map/gap
60) Forcefully restart/shutdown window (write cmd in RUN)
shutdown -r -f -t 00
shutdown -s -f -t 00
61) View detailed info about installed package.
dpkg --status apache2
62) See last reboot log details
last reboot
63) Show process details in advance
iotop , iostat , atop
64) SHow history with date and time
echo 'HISTTIMEFORMAT="%F %T "' >> ~/.bashrc
65) Replace the word from file
sed 's/unix/linux/g' demofile.txt
66) Show All Hidden Files
du -sh .[^.]*
67) Find Out which process is eating much CPU & RAM
ps -eo pmem,pcpu,pid,user,args | sort -k 1 -r | head -10
68) Make it short terminal host
export PS1="\u$"
69) Install Multiple Services In Single Command
sudo sh -c 'apt update && apt install vim'
70) who and w (This command shows the information about the users currently on the machine and their processes.)
who and w
Kill Remotey Connected User Terminal Access Only (after w cmd)
sudo pkill -9 -t pts/5
71) It Will Kill All Process Which Are Running By User
pkill -u user_name
72) If You Get 1 For hard disks & 0 for a SSD.
cat /sys/block/sda/queue/rotational
73) trash-list , trash-restore
sudo apt-get install trash-cli
74) Find a Specific Word in a File
$ grep -Rnw '/home/ubuntu/Desktop' -e 'India'
Reduce Unnecessary timing to find exact word
$ grep --exclude=*.csv -Rnw '/home/ubuntu/Desktop' -e 'India'
75) Excute Commands Without Login SSH Terminal
ssh root@10.10.3.4 'uptime'
ssh root@10.10.3.4 'ls /var/www/html/'
76) Make a User an Administrator in Ubuntu via cli
sudo adduser user_name sudo
77) Locate command is an reliable & better alternative of find cmd.
locate -b demo-file.txt
78 ) ......To Be Continue
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