bash-review.md

Bash

• IO redirection: > and <
• Different types of quotes: ' vs "
• ~/.bashrc vs ~/.profile: Environment-based vs Local-user based
• source vs ./ vs running script using name:
• The terminal you are in is a process. That process also uses your configuration files as they were when you logged in / opened the terminal. When you run the script using ./ Or via the command name, it runs as its own process (think virtual window). You could toss in a sleep command and see it sitting there with ps. Because the script is it's own process, .bashrc is getting reloaded, but not for your shell - for the virtual shell.
• ./ for script is a direct path to a file name
• script name uses implied $PATH env var if file found
• Source Keyword uses current working shell/terminal - any command ran in script, activates on screen
• Variables and accessing variable values: varName vs $varName ($ is for usage)
• Use arguments: using scriptname $1 vs $1 inside bash script inside function
  • In a script
  • In a script function
• Conditionals (using the test command): [ vs [[ - Single for Keywords, Double for Keywords + arithmetic compares, use with && echo true/false
• if statements: if [ conditional ]; then statement; fi
• functions