CLI and Scripts Basics

Table of Contents


We present here a quick guide on different command-line interface (CLI) commands as well as some basic scripts.

The main goal of this guide is to demonstrate that having some core understanding of CLI and scripts can drastically increase efficiency and speed when it comes to deploying and managing workloads on the TFGrid.

Basic Commands

Update and upgrade packages

The command update ensures that you have access to the latest versions of packages available.

sudo apt update

The command upgrade downloads and installs the updates for each outdated package and dependency on your system.

sudo apt upgrade

Test the network connectivity of a domain or an IP address with ping

To test the network connectivity of a domain or an IP address, you can use ping on Linux, MAC and Windows:

  • Template
    ping <IP-Address_Or_Domain>
  • Example

On Windows, by default, the command will send 4 packets. On MAC and Linux, it will keep on sending packets, so you will need to press Ctrl-C to stop the command from running.

You can also set a number of counts with -c on Linux and MAC and -n on Windows.

  • Send a given number of packets on Linux and MAC (e.g 5 packets)
    ping -c 5
  • Send a given number of packets on Windows (e.g 5 packets)
    ping -n 5

Install Go

Here are the steps to install Go.

  • Install go
    • sudo apt install golang-go
  • Verify that go is properly installed
    • go version

Install Brew

Follow those steps to install Brew

  • Installation command from Brew:
    • /bin/bash -c "$(curl -fsSL"
  • Add the path to the .profile directory. Replace <user_name> by your username.
    • echo 'eval "$(/home/linuxbrew/.linuxbrew/bin/brew shellenv)"' >> /home/<user_name>/.profile
  • Evaluation the following:
    • eval "$(/home/linuxbrew/.linuxbrew/bin/brew shellenv)"
  • Verify the installation
    • brew doctor

Brew basic commands

  • To update brew in general:
    • brew update
  • To update a specific package:
    • brew update <package_name>
  • To install a package:
    • brew install <package_name>
  • To uninstall a package:
    • brew uninstall <package_name>
  • To search a package:
    • brew search <package_name>
  • Uninstall Brew
    • /bin/bash -c "$(curl -fsSL"

Install Terraform with Brew

Installing Terraform with Brew is very simple by following the Terraform documentation.

  • Compile HashiCorp software on Homebrew's infrastructure
    • brew tap hashicorp/tap
  • Install Terraform
    • brew install hashicorp/tap/terraform

Yarn basic commands

  • Add a package
    • yarn add
  • Initialize the development of a package
    • yarn init
  • Install all the dependencies in the package.json file
    • yarn install
  • Publish a package to a package manager
    • yarn publish
  • Remove unused package from the current package
    • yarn remove
  • Clean the cache
    • yarn cache clean

Set default terminal

update-alternatives --config x-terminal-emulator

See the current path


List hidden files

ls -ld .?*

Display the content of a directory

You can use tree to display the files and organization of a directory:

  • General command
    • tree
  • View hidden files
    • tree -a

Vim modes and basic commands

Vim is a free and open-source, screen-based text editor program.

With Vim, you can use two modes.

  • Insert mode - normal text editor
    • Press i
  • Command mode - commands to the editor
    • Press ESC

Here are some basic commands:

  • Delete characters
    • x
  • Undo last command
    • u
  • Undo the whole line
    • U
  • Go to the end of line
    • A
  • Save and exit
    • :wq
  • Discard all changes
    • :q!
  • Move cursor to the start of the line
    • 0
  • Delete the current word
    • dw
  • Delete the current line
    • dd

Check the listening ports using netstat

Use the command:


See the disk usage of different folders

du -sh *

Verify the application version

which <application_name>

Find the path of a file with only the file name

On MAC and Linux, you can use coreutils and realpath from Brew:

  • brew install coreutils
  • realpath file_name

Become the superuser (su) on Linux

You can use either command:

  • Option 1
    • sudo -i
  • Option 2
    • sudo -s

Exit a session

You can use either command depending on your shell:

  • exit
  • logout

Know the current user

You can use the following command:

  • whoami

See the path of a package

To see the path of a package, you can use the following command:

  • whereis <package_name>

Set the path of a package

export PATH=$PATH:/snap/bin

See the current path


Find the current shell

  • Compact version
    • echo $SHELL
  • Detailed version
    • ls -l /proc/$$/exe

SSH into Remote Server

  • Create SSH key pair
    • ssh-keygen
  • Install openssh-client on the local computer*
    • sudo apt install openssh-client
  • Install openssh-server on the remote computer*
    • sudo apt install openssh-server
  • Copy public key
    • cat ~/.ssh/
  • Create the ssh directory on the remote computer
    • mkdir ~/.ssh
  • Add public key in the file authorized_keys on the remote computer
    • nano ~/.ssh/authorized_keys
  • Check openssh-server status
    • sudo service ssh status
  • SSH into the remote machine
    • ssh <username>@<remote_server_IP_or_hostname>

*Note: For MAC, you can install openssh-server and openssh-client with Brew: brew install openssh-server and brew install openssh-client.

To enable remote login on a MAC, read this section.

Replace a string by another string in a text file

  • Replace one string by another (e.g. old_string, new_string)
    • sed -i 's/old_string/new_string/g' <file_path>/<file_name>
  • Use environment variables (double quotes)
    • sed -i "s/old_string/$env_variable/g" <file_path>/<file_name>

Replace extensions of files in a folder

Replace ext1 and ext2 by the extensions in question.

find ./ -depth -name "*.ext1" -exec sh -c 'mv "$1" "${1%.ext1}.ext2"' _ {} \;

Remove extension of files in a folder

Replace ext with the extension in question.

for file in *.ext; do
    mv -- "$file" "${file%%.ext}"

See the current date and time on Linux


Special variables in Bash Shell

Special VariablesDescriptions
$0Name of the bash script
$1, $2...$nBash script arguments
$$Process id of the current shell
$*String containing every command-line argument
$#Total number of arguments passed to the script
$@Value of all the arguments passed to the script
$?Exit status of the last executed command
$!Process id of the last executed command
$-Print current set of option in current shell

Gather DNS information of a website

You can use Dig to gather DNS information of a website

  • Template
    • dig <website.tld>
  • Example
    • dig

You can also use online tools such as DNS Checker.

Partition and mount a disk

We present one of many ways to partition and mount a disk.

  • Create partition with gparted
    • sudo gparted
  • Find the disk you want to mount (e.g. sdb)
    • sudo fdisk -l
  • Create a directory to mount the disk to
    • sudo mkdir /mnt/disk
  • Open fstab
    • sudo nano /etc/fstab
  • Append the following to the fstab with the proper disk path (e.g. /dev/sdb) and mount point (e.g. /mnt/disk)
    • /dev/sdb    /mnt/disk    ext4    defaults    0    0
  • Mount the disk
    • sudo mount /mnt/disk
  • Add permissions (as needed)
    • sudo chmod -R 0777 /mnt/disk


Encrypt files with Gocryptfs

You can use gocryptfs to encrypt files.

  • Install gocryptfs
    • apt install gocryptfs
  • Create a vault directory (e.g. vaultdir) and a mount directory (e.g. mountdir)
    • mkdir vaultdir mountdir
  • Initiate the vault
    • gocryptfs -init vaultdir
  • Mount the mount directory with the vault
    • gocryptfs vaultdir mountdir
  • You can now create files in the folder. For example:
    • touch mountdir/test.txt
  • The new file test.txt is now encrypted in the vault
    • ls vaultdir
  • To unmount the mountedvault folder:
    • Option 1
      • fusermount -u mountdir
    • Option 2
      • rmdir mountdir

Encrypt files with Veracrypt

To encrypt files, you can use Veracrypt. Let's see how to download and install Veracrypt.

  • Veracrypt GUI
    • Download the package
      • wget
    • Install the package
      • dpkg -i ./veracrypt-1.25.9-Ubuntu-22.04-amd64.deb
  • Veracrypt console only
    • Download the package
      • wget
    • Install the package
      • dpkg -i ./veracrypt-console-1.25.9-Ubuntu-22.04-amd64.deb

You can visit Veracrypt download page to get the newest releases.

  • To run Veracrypt
    • veracrypt
  • Veracrypt documentation is very complete. To begin using the application, visit the Beginner's Tutorial.

See the network connections and ports


See identity and info of IP address

  • See abuses related to an IP address:
  • See general information of an IP address:

ip basic commands

  • Manage and display the state of all network
    • ip link
  • Display IP Addresses and property information (abbreviation of address)
    • ip addr
  • Display and alter the routing table
    • ip route
  • Manage and display multicast IP addresses
    • ip maddr
  • Show neighbour object
    • ip neigh
  • Display a list of commands and arguments for each subcommand
    • ip help
  • Add an address
    • Template
      • ip addr add
    • Example: set IP address to device enp0
      • ip addr add dev enp0
  • Delete an address
    • Template
      • ip addr del
    • Example: set IP address to device enp0
      • ip addr del dev enp0
  • Alter the status of an interface
    • Template
      • ip link set
    • Example 1: Bring interface online (here device em2)
      • ip link set em2 up
    • Example 2: Bring interface offline (here device em2)
      • ip link set em2 down
  • Add a multicast address
    • Template
      • ip maddr add
    • Example : set IP address to device em2
      • ip maddr add 33:32:00:00:00:01 dev em2
  • Delete a multicast address
    • Template
      • ip maddr del
    • Example: set IP address to device em2
      • ip maddr del 33:32:00:00:00:01 dev em2
  • Add a routing table entry
    • Template
      • ip route add
    • Example 1: Add a default route (for all addresses) via a local gateway
      • ip route add default via dev em1
    • Example 2: Add a route to via the gateway at
      • ip route add via
    • Example 3: Add a route to that can be reached on device em1
      • ip route add dev em1
  • Delete a routing table entry
    • Template
      • ip route delete
    • Example: Delete the route for via the gateway at
      • ip route delete via
  • Replace, or add, a route
    • Template
      • ip route replace
    • Example: Replace the defined route for to use device em1
      • ip route replace dev em1
  • Display the route an address will take
    • Template
      • ip route get
    • Example: Display the route taken for IP
      • ip route replace dev enp0


Display socket statistics

  • Show all sockets
    • ss -a
  • Show detailed socket information
    • ss -e
  • Show timer information
    • ss -o
  • Do not resolve address
    • ss -n
  • Show process using the socket
    • ss -p

Note: You can combine parameters, e.g. ss -aeo.


Query or control network driver and hardware settings

  • Display ring buffer for a device (e.g. eth0)
    • ethtool -g eth0
  • Display driver information for a device (e.g. eth0)
    • ethtool -i eth0
  • Identify eth0 by sight, e.g. by causing LEDs to blink on the network port
    • ethtool -p eth0
  • Display network and driver statistics for a device (e.g. eth0)
    • ethtool -S eth0


See if ethernet port is active

Replace <ethernet_device> with the proper device:

cat /sys/class/net/<ethernet_device>/carrier

Add IP address to hardware port (ethernet)

  • Find ethernet port ID on both computers

    • ip a
  • Add IP address (DHCO or static)

    • Computer 1
      • ip addr add <Private_IP_Address_1>/24 dev <ethernet_interface_1>
    • Computer 2
      • ip addr add <Private_IP_Address_2>/24 dev <ethernet_interface_2>
  • Ping the address to confirm connection

    • ping <Private_IP_Address>

To set and view the address for either DHCP or static, go to Networks then Details.

Private IP address range

The private IP range is the following:


Set IP Address manually

You can use the following template when you set an IP address manually:

  • Address
    • <Private_IP_Address>
  • Netmask
  • Gateway
    • optional

Basic Scripts

Run a script with arguments

You can use the following template to add arguments when running a script:

  • Option 1
    • ./ arg1 arg2
  • Option 2
    • sh "arg1" "arg2"
  • Write a script
    • File:
    • #!/bin/sh
      echo $@
  • Give permissions
    • chmod +x ./
  • Run the script with arguments
    • sh arg1 arg2

Iterate over arguments

  • Write the script

    •   #
        for i; do 
          echo $i 
  • Give permissions

    • chmod +x ./
  • Run the script with arguments

    • sh arg1 arg2
  • The following script is equivalent

    •   #
        for i in $*; do 
          echo $i 

Count lines in files given as arguments

  • Write the script
    • #
       for i in $*; do
              nlines=$(wc -l < $i)    
              echo "There are $nlines lines in $i"
  • Give permissions
    • chmod +x ./
  • Run the script with arguments (files). Here we use the script itself as an example.
    • sh

Find path of a file

  • Write the script
    • #
      find / -iname $1 2> /dev/null
  • Run the script
    • sh <filename>
  • Write the script
    • #
      echo This script was passed $# arguments
  • Run the script
    • sh <filename>


Install Terraform

Here are the steps to install Terraform on Linux based on the Terraform documentation.

wget -O- | sudo gpg --dearmor -o /usr/share/keyrings/hashicorp-archive-keyring.gpg
echo "deb [signed-by=/usr/share/keyrings/hashicorp-archive-keyring.gpg] $(lsb_release -cs) main" | sudo tee /etc/apt/sources.list.d/hashicorp.list
sudo apt update && sudo apt install terraform

Note that the Terraform documentation also covers other methods to install Terraform on Linux.


Enable remote login on MAC

  • Option 1:
    • Use the following command line:
      • systemsetup -setremotelogin on
  • Option 2
    • Use System Preferences
    • Go to System Preferences -> Sharing -> Enable Remote Login.

Find Other storage on MAC

  • Open Finder > Go > Go to Folder
  • Paste this path
    • ~/Library/Caches

Sort files by size and extension on MAC

  • From your desktop, press Command-F.
  • Click This Mac.
  • Click the first dropdown menu field and select Other.
  • From the Search Attributes window
    • tick File Size and File Extension.


Install Chocolatey

To install Chocolatey on Windows, we follow the official Chocolatey website instructions.

  • Run PowerShell as Administrator
  • Check if Get-ExecutionPolicy is restricted
    • Get-ExecutionPolicy
    • If it is restricted, run the following command:
      • Set-ExecutionPolicy AllSigned
  • Install Chocolatey
    • Set-ExecutionPolicy Bypass -Scope Process -Force; [System.Net.ServicePointManager]::SecurityProtocol = [System.Net.ServicePointManager]::SecurityProtocol -bor 3072; iex ((New-Object System.Net.WebClient).DownloadString(''))
  • Note: You might need to restart PowerShell to use Chocolatey

Install Terraform with Chocolatey

Once you've installed Chocolatey on Windows, installing Terraform is as simple as can be:

  • Install Terraform with Chocolatey
    • choco install terraform

Find the product key

Write the following in Command Prompt (run as administrator):

wmic path SoftwareLicensingService get OA3xOriginalProductKey

Find Windows license type

Write the following in Command Prompt:

slmgr /dli


  • GNU Bash Manual -
Last change: 2024-02-27