Summary

Bash is a unix_shell and command language. It runs in the command_line on Linux and macOS. You type commands with options and arguments. Use pipes and redirection to connect programs and files. Store data in variables and the environment. Write scripts with a shebang, then set permissions to run them. Control text with quoting and wildcards. Core builtins include cd, echo, and export. Check exit_status values, where 0 means success. Know your path and working_directory. Use history to repeat commands.