BASH practice over time

Using Learning the bash Shell, 3rd edition as basis for exercises, also doing own implementations

Reads input file, orders input file lines in reverse numerical order and prints n lines to the screen using user input or default value.

uses [ condition ] to show how they work in general compares strings and if a file actually exists

Contains albumscript.sh and albumcounter files give albumcounter as argument for albumscript.sh

Cuts a column from a file with multiple columns of data randomdata contains the data cutdata.sh uses

Demonstrates that variables inside functions are not global to the whole script Give data such as aa bb cc dd when running the script

Selects files that match a given argument such as a specific month

Changes image format from jpg to jpeg To run again manually change from jpeg back to jpg Uses images.jpg

checks if a string is null using -n, ! -n, -z and ! -z operations

Demonstrates that {} are necessary wrappers for shell variables in following scenarios: variable number is >= 10 or when wanting to add lets say character _ or a longer string after a specific variable.

Showcases how to join different variables together and how to cut specific parts from a variable

Checks if a service is running or not accepts service name as $1 argument

compares two strings using =, != operations

Taken from Learning the bash shell, 3rd edition Navigates inside further directories and prints said directories

Retrieves users that are logged in and tries to send them a message up to logged in terminal number 6.