http://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html

• Parser
  • Basic line parser
  • Comments
  • Quoting, escaping
  • Aliases
  • Parameters, variables
  • Word expansions
    • Parameter expansion
      • Variables
      • Expressions
    • Command substitution
      • `…`
      • $(…)
    • Arithmetic expansion
  • Redirections
    • Redirecting IO
    • Here-document
  • Pipelines
  • Async lists
  • Compound commands
    • {…}
    • (…)
  • Control structures
    • if, elif, else, fi
    • while, for, until, do, done
    • case, in, esac
  • Function definition
• Shell
  • Simple commands
  • Redirections
    • Redirecting IO
    • Here-document
  • Pipelines
  • and-or lists
  • Async lists
  • Compound commands
    • {…}
    • (…)
  • Parameters, variables
    • Shell variables
    • Positional parameters, special parameters
  • Word expansions
    • Tilde expansion
    • Parameter expansion
      • Variables
      • Expressions
    • Command substitution
    • Arithmetic expansion
    • Field splitting
    • Pathname expansion
    • Quote removal
  • Control structures
    • Conditions
    • Loops
    • Case
  • Aliases
  • Function definition
  • CLI flags
  • Job control
  • Exit status and errors
  • Signals and error handling
  • Pattern matching
• POSIX build system
• Special builtins
  • break
  • : (colon)
  • continue
  • . (dot)
  • eval
  • exec
  • exit
  • export
  • readonly
  • return
  • set
  • shift
  • times
  • trap
  • unset
• Regular builtins
  • type
  • ulimit
  • alias
  • bg
  • cd
  • command
  • false
  • fg
  • getopts
  • hash
  • jobs
  • pwd
  • read
  • true
  • umask
  • unalias
  • wait