1Shells and Shell Scripting

• 1.1Customizing the Shell Environment

  Learn the configuration files read at login and shell startup: system-wide (/etc/profile, /etc/bash.bashrc) vs per-user (~/.bash_profile, ~/.bash_login, ~/.profile, ~/.bashrc, ~/.bash_logout) and their order, command substitution with alias, setting PATH, ./source, and lists (;, &&, ||).

• 1.2Shell Scripting

  Learn shell scripting—the heaviest topic on exam 102 (weight 6): the shebang (#!), execute permissions (chmod, chown), positional parameters ($0, $1..$n, $#, $*, $@, shift), exit status ($?, exit), conditionals (if, case), loops (for, while), shell functions, PATH-independent scripts, and debugging (bash -x, bash -v).