simple resource list

all the links to work

1. 01_shell_basics.
2. 02_navigating_file_system.
3. 03_doing_things_with_files.
4. 04_echoing_variables.
5. 05_scripts.
6. 06_command-line_tools.
7. 07_youtube-dl_challenge.
8. images.
9. xx_drafts_and_ideas.