Networking
Ping 1 Time
ping google.com -c 1 #c is abbreviation for count
Check Networking
ifconfig
ip addr
How to Check Open Ports
sudo netstat -tulpn #Shows address and port
System Admin
Emulate root
sudo -s #This prevents the system from asking for the sudo password after timer expires
exit #exit sudo mode
Emulate another user
su kimconnect #To become the user kimconnect
exit #end user masquerade
How to check kernel version
uname -a
Trigger a system checkup on next reboot
sudo touch /forcefsck
Timed Shutdown
sudo shutdown -h 5 #Shutdown. Halt everything in 5 minutes
Cancel Shutdown timer
sudo shutdown -c
Check CPU usage of PHP
ps aux | grep apached
Check CPU/Memory Usage of All Processes
top #preinstalled in most systems
htop #new top package, human readable
Check Services
service SERVICENAME status #Older unix command
systemctl status SERVICENAME #Systemd command
Stop Processes
killall PROCESSNAME #instantly halt a process and its related
pkill #similar to killall with more chances of success
File & Folder Manipulations
Get folder size
sudo du -sh /var
admin@nfs:~# sudo du -shc /export/pihole
108M /export/pihole
108M total
sudo du -h --max-depth=2 /export/pihole
admin@nfs:~# sudo du -h --max-depth=2 /export/pihole
8.0K /export/pihole/dnsmasq
8.0K /export/pihole/pihole/migration_backup
108M /export/pihole/pihole
108M /export/pihole
List hidden files
ls -la #long format, all files
Check Disk Space
df -ah #disk free all human readable
Check folder/directory size
du -sh /var/www/html #disk usage sum human readable
Find Universal Identifier for Drives (UUID)
sudo blkid
Check for Existing Mounts
mount
How to Create a Mount
mount /dev/sda2 /mnt #sda2 = disk 1 partition 2
Check for Persistent Mounts (Mounts at Bootup)
less /etc/fstab
Create a file
touch testfile.txt #This command also updates the last modified time attribute
Move and rename a file
mv file1.txt ~/file1.txt_backup #Move file1.txt into home directory and rename it with a _backup suffix
Find the directory where an App is installed
which google-chrome
less is the same as more + cat
less somefile.txt
cat somefile.txt | more
Search for a phrase inside a file
grep -i kimconnect.com domains.txt #Ignore case during grep
strings domains.txt | grep kimconnect.com | less #Alternative method
Count lines, words, and letters
wc domains.txt
Switch between different files
vi text1.txt
Keys Combo: Control+Z
vi text2.txt
Keys Combo: Control+Z
jobs #Shows tasks in the background
fg %2 #Join the job index
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