Common Tasks and commands

Some every day tasks:

 

ls – List Files

ls -lha

List all files in the current directory, including hidden files.

 cd – Change directory

cd /etc

In this example, change to the /etc directory.
pwd – Print Working Directory

pwd

Prints the current working directory. Useful in cases we want to make sure we are in the right directory.

 mkdir – Make Direcory

mkdir -p ~/catkin_ws

Create a directory. In this example we create a directory called catkin_ws under oure home directory. The -p switch create the parent directory structure.

Updating and Upgrading the System

It is very important to keep the system up to date. The most obvious reasons are Security and Bug fixes. An up-to-date system runs faster and smoother….

The update consists of a few stages, laid out in the following table. To  update your Ubuntu system, open a terminal and execute the following commands in the following order:

Command Explanation
sudo apt-get update Update the local repositories’ cache against the online repositories.

This will create a local copy (cache) of the packages available for installation.
sudo apt-get upgrade Upgrade the installed packages.  This will download the packages from the remote repositories and install them.
sudo apt-get dist-upgrade Install missing dependencies. This will install any missing dependencies first, and then install the rest of the updates.
sudo apt-get autoremove Remove redundant packages.  This command removes installed packages that are no longer required, usually packages that were installed as dependencies.
sudo apt-get clean Delete downloaded packages. This command deletes packge files downloaded during the upgrade process, saving space.