BNF for bash

D.2 BNF for bash

The following is the syntax of bash 2.0 in Backus-Naur Form (BNF):

  <letter> ::= abcdefghijklmnopqrstuvwxyz  

  ABCDEFGHIJKLMNOPQRSTUVWXYZ  

  <digit> ::= 0123456789  

  <number> ::= <digit>  

  <number> <digit>  

  <word> ::= <letter>  

  <word> <letter>  

  <word> '_'  

  <word_list> ::= <word>  

  <word_list> <word>  

  <assignment_word> ::= <word> '=' <word>  

  <redirection> ::= '>' <word>  

  '<' <word>  

  <number> '>' <word>  

  <number> '<' <word>  

  '>>' <word>  

  <number> '>>' <word>  

  '<<' <word>  

  <number> '<<' <word>  

  '<&' <number>  

  <number> '<&' <number>  

  '>&' <number>  

  <number> '>&' <number>  

  '<&' <word>  

  <number> '<&' <word>  

  '>&' <word>  

  <number> '>&' <word>  

  '<<-' <word>  

  <number> '<<-' <word>  

  '>&' '-'  

  <number> '>&' '-'  

  '<&' '-'  

  <number> '<&' '-'  

  '&>' <word>  

  <number> '<>' <word>  

  '<>' <word>  

  '>' <word>  

  <number> '>' <word>  

  <simple_command_element> ::= <word>  

  <assignment_word>  

  <redirection>  

  <redirection_list> ::= <redirection>  

  <redirection_list> <redirection>  

  <simple_command> ::= <simple_command_element>  

  <simple_command> <simple_command_element>  

  <command> ::= <simple_command>  

  <shell_command>  

  <shell_command> <redirection_list>  

  <shell_command> ::= <for_command>  

  <case_command>  

  while <compound_list> do <compound_list> done  

  until <compound_list> do <compound_list> done  

  <select_command>  

  <if_command>  

  <subshell>  

  <group_command>  

  <function_def>  

  <for_command> ::= for <word> <newline_list> do <compound_list> done  

  for <word> <newline_list> '{' <compound_list> '}'  

  for <word> ';' <newline_list> do <compound_list> done  

  for <word> ';' <newline_list> '{' <compound_list> '}'  

  for <word> <newline_list> in <word_list> <list_terminator>  

  <newline_list> do <compound_list> done  

  for <word> <newline_list> in <word_list> <list_terminator>  

  <newline_list> '{' <compound_list> '}'  

  <select_command> ::= select <word> <newline_list> do <list> done  

  select <word> <newline_list> '{' <list> '}'  

  select <word> ';' <newline_list> do <list> done  

  select <word> ';' <newline_list> '{' list '}'  

  select <word> <newline_list> in <word_list>  

  <list_terminator> <newline_list> do <list> done  

  select <word> <newline_list> in <word_list>  

  <list_terminator> <newline_list> '{' <list> '}'  

  <case_command> ::= case <word> <newline_list> in <newline_list> esac  

  case <word> <newline_list> in <case_clause_sequence>  

  <newline_list> esac  

  case <word> <newline_list> in <case_clause> esac  

  <function_def> ::= <word> '(' ')' <newline_list> <group_command>  

  function <word> '(' ')' <newline_list> <group_command>  

  function <word> <newline_list> <group_command>  

  <subshell> ::= '(' <compound_list> ')'  

  <if_command> ::= if <compound_list> then <compound_list> fi  

  if <compound_list> then <compound_list> else <compound_list> fi  

  if <compound_list> then <compound_list> <elif_clause> fi  

  <group_command> ::= '{' <list> '}'  

  <elif_clause> ::= elif <compound_list> then <compound_list>  

  elif <compound_list> then <compound_list> else <compound_list>  

   elif <compound_list> then <compound_list> <elif_clause> 

 <case_clause> ::= <pattern_list> 

 <case_clause_sequence> <pattern_list> 

 <pattern_list> ::= <newline_list> <pattern> ')' <compound_list> 

 <newline_list> <pattern> ')' <newline_list> 

 <newline_list> '(' <pattern> ')' <compound_list> 

 <newline_list> '(' <pattern> ')' <newline_list> 

 <case_clause_sequence> ::= <pattern_list> ';;' 

 <case_clause_sequence> <pattern_list> ';;' 

 <pattern> ::= <word> 

 <pattern> '' <word> 

 <list> ::= <newline_list> <list0> 

 <compound_list> ::= <list> 

 <newline_list> <list1> 

 <list0> ::= <list1> '\n' <newline_list> 

 <list1> '&' <newline_list> 

 <list1> ';' <newline_list> 

 <list1> ::= <list1> '&&' <newline_list> <list1> 

 <list1> '' <newline_list> <list1> 

 <list1> '&' <newline_list> <list1> 

 <list1> ';' <newline_list> <list1> 

 <list1> '\n' <newline_list> <list1> 

 <pipeline_command> 

  <list_terminator> ::= '\n'  

  ';'  

  <newline_list> ::=  

  <newline_list> '\n'  

  <simple_list> ::= <simple_list1>  

  <simple_list1> '&'  

  <simple_list1> ';'  

  <simple_list1> ::= <simple_list1> '&&' <newline_list> <simple_list1>  

  <simple_list1> '' <newline_list> <simple_list1>  

  <simple_list1> '&' <simple_list1>  

  <simple_list1> ';' <simple_list1>  

  <pipeline_command>  

  <pipeline_command> ::= <pipeline>  

  '!' <pipeline>  

  <timespec> <pipeline>  

  <timespec> '!' <pipeline>  

  '!' <timespec> <pipeline>  

  <pipeline> ::=  

  <pipeline> '' <newline_list> <pipeline>  

  <command>  

  <time_opt> ::= '-p'  

  <timespec> ::= time  

  time <time_opt>  

  .XE "BNF (Backus-Naur Form)"  

  .XE "bash" "syntax, BNF form of"