Useful snippets for networking that I use repeatedly

networking-besties.sh

# HSTS status
curl -s -D- https://example.com/ | grep -i Strict

ssh-keygen -t rsa -b 4096 -f ~/.ssh/github_rsa -C "username@hostname"
ssh-keygen -t ed25519 -C "[email protected]" -f ~/.ssh/github_ed25519

# Basic add user with SSH
sudo adduser <USER>
sudo su <USER>
ssh-keygen
cd ~/.ssh
nano authorized_keys
    Add public key
chmod 644 authorized_keys
exit
# optional or add to wheel
sudo visudo
    <USER> ALL=(ALL) NOPASSWD:ALL
# Del user and home
    sudo userdel -r <USER>

# File view and edit
nano file.txt        # to edit file.txt
cat file.txt         # to view file.txt
less file.txt        # to view with scrolling capabilities
head file.txt        # to view the first 10 lines
head -n 5 file.txt   # to view the first 5 lines 
tail file.txt        # to view the last 10 lines 
tail -n 5 file.txt   # to view the last 5 lines

# Search in files
grep hello file.txt        # to search for hello in file.txt
grep -i hello file.txt     # case-insensitive search 
grep -i hello file*.txt    # to search in files with a pattern
grep -i -r hello .         # to search in the current directory

# Search for files and directories
locate             # find a string
find               # to list all files and directories
find -type d       # to list directories only
find -type f       # to list files only
find -name “f*”    # to filter by name using a pattern

# Env variables
printenv           # to list all variables and their value
printenv PATH      # to view the value of PATH
echo $PATH         # to view the value of PATH
export name=bob    # to set a variable in the current session

# Install by creating a .deb

# Verify that you have all required tools
sudo apt-get install python g++ make checkinstall fakeroot
# Create tmp dir and switch to it
src=$(mktemp -d) && cd $src
# Download the latest version of Node
wget -N http://nodejs.org/dist/node-latest.tar.gz
# Extract the content of the tar file
tar xzvf node-latest.tar.gz && cd node-v*
# Run configuration
./configure
# Create .deb for Node
sudo fakeroot checkinstall -y --install=no --pkgversion $(echo $(pwd) | sed -n -re's/.+node-v(.+)$/\1/p') make -j$(($(nproc)+1)) install
# Replace [node_*] with the name of the generated .deb package of the previous step
sudo dpkg -i node_*

# Install
sudo mv Postman-linux-x64-8.6.2.tar.gz /opt/
cd /opt
sudo tar xzvf Postman-linux-x64-8.6.2.tar.gz
sudo rm Postman-linux-x64-8.6.2.tar.gz
sudo ln -s /opt/Postman/Postman /usr/local/bin/postman # symbolic link
touch ~/.local/share/applications/postman.desktop # create desktop gui file
# add to file
[Desktop Entry]
Name=Postman
GenericName=API Client
X-GNOME-FullName=Postman API Client
Comment=Make and view REST API calls and responses
Keywords=api;
Exec=/usr/local/bin/postman
Terminal=false
Type=Application
Icon=/opt/Postman/app/resources/app/assets/icon.png
Categories=Development;Utilities;