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Commonly used commands
date -d @1626647940
sudo systemctl restart network-manager
sudo gparted
nmap -sP 192.168.0.1/24 scan ports
nmap -A 192.168.10.112 detect OS and services
ls -l /dev/ttyS0
groups <username>
sudo gpasswd -a <username> <groupname>
sudo gpasswd -d <username> <groupname>
sudo groupadd <newgroupname>
sudo usermod -a -G <groupname> <username>
which pip to see which pip command you are running - useful for checking environment!
lsusb to check USB devices
lspci to check PCI devices
lspci | grep VGA to check GPUs
sudo lshw -C video to check GPU display details
uncomment #force_color_prompt=yes in .bashrc for a colored prompt
sudo !! where !! is for the last command
python3 -m site show searching path for python3
sudo python -m pip install --force-reinstall pip==8.1.1 if you inadvertently upgraded your system pip. More info can be found at this link, and this link.
sudo ldconfig after sudo make install to refresh the cache
tar -cf filename.tar file1 folder2 packed without compression
tar -xf filename.tar
tar -cvzf filename.tar.gz file1 folder2 compress by -z; verbose by -v
tar -xvzf filename.tar.gz 
tar -xvzf filename.tar.gz -C {path} decompress to a designated path
running in the background
Ctrl + Z to stop the process, followed by bg to run in the background or fg to run in the foreground.
Use command ./test.sh 1>stdout.log 2>stderr.log & and it will return a process ID. 
Processes running in the background can be monitored by top command. 
apt commands to find dependencies (link)
apt-cache showpkg <pkgname>  show package info, both depends and reverse depends
apt-cache depends ros-melodic-desktop show one-level dependencies
apt-cache rdepends --installed ros-melodic-desktop 
sudo apt install apt-rdepends
apt-rdepends ros-melodic-desktop | pager recursively show all dependencies 
apt-rdepends --reverse protobuf-compiler | grep ros-melodic-desktop  
apt commands to locate packages
dpkg -L <package-name>
apt list <package-name>
apt-cache madison  
locate <filename> find a file in database (globally)
find <filename> find a file in local directory
vim commands
vi -b <filename> open file in binary mode
:%!xxd switch to hex mode
:%!xxd -r switch back to binary mode
:wq save and exit
terminal
sudo update-alternatives --config x-terminal-emulator
SSH Commands
ssh to see if ssh is installed (openssh-client is installed by default)
ssh-keygen or ssh-keygen -t rsa generate ssh key by RSA algorithm
cat ~/.ssh/id_rsa.pub print public key (for settings on Github)
ssh -T [email protected] testing
sudo apt-get install openssh-server install server for incoming ssh connections
ssh-copy-id username@hostname copy your ssh key to remote computer to avoid verifying password on every connection
ssh username@ip ssh login to a remote computer with this ip and username
ssh username@hostname if mapped this hostname to its ip in /etc/hosts file
ssh -X username@hostname login with GUI open
ssh -p 1234 username@hostname login via port 1234
sudo gedit /etc/hosts modify hosts file
sudo gedit /etc/ssh/sshd_config modify ssh server configuration
References: The Unix Shell; 
Development - Previous
Linux
GDB
Last modified 2yr ago