bash-hackers-wiki/docs/syntax/ccmd/intro.md

Bash compound commands

The main part of Bash's syntax are the so-called compound commands. They're called like that because they use "real" commands (simple commands or lists) and knit some intelligence around them. That is what the essential "Bash language" is made of.

Command grouping

• grouping: command grouping
• grouping again: command grouping in a subshell

Conditional reactions

Note that conditionals can also be scripted using list, which are syntax elements, not commands.

• the "new" test command: conditional expression
• if-clause: conditional branching
• case statement: pattern-based branching

Loops

• classic for-loop
• C-style for-loop
• while loop
• until loop

Misc

• math: arithmetic evaluation
• menus: user selections