42sh

A 42 school project. A bash style shell with some features from Oh my Zsh. Made with 4 persons. A bash style shell with some features from Oh my Zsh. The project follow the C Norme of 42 school. if you dont see any 'for' or 'case', or have to witness some awful code, dont be surprised, blame the Norme ! 42 - Norme

DISCLAIMER

The following list of features is not accurate, some have been removed from the project because unstable, while some do not figure in the list. The features presented in the following document should be here and enable relatively experienced user to use this shell without too much discomfort. 42 - 42sh Subject

How to

Requirements

• Termcap Lirary

Termcap being as old as it is, it can be complicated to get the library setup on some systems.

Installing

git clone https://github.com/ade-sede/42sh.git 42sh
cd 42sh && make

Running

./42sh

The line editing does not work anymore and seems to lock / misbehave all the time. This is because we were forced to use the TERMCAP library as part of the school subject. Termcap was already obsolete 15 years ago ... In order to work again we would need to replace Termcap with Ncurses .

You can still test execution of commands and scripts using the following command.

./42sh -c "<command>"

Syntax coloring

set -o syncolor

Line editing

Keys	Functions
Opt+v Opt+c Opt+p	Enter visual mode Copy Paste
Opt+← Opt+→	Move per words.
Opt+↑ Opt+↓	Move per line.

History

Keys	Functions
↑ ↓	Browse the history.
Ctrl+R	Back Search.
!!	Retype the last command.
!n	Retype the n(numerical value) command from the begin of history.
!-n	Retype the -n(numerical value) command from the last command.
!name	Search for a command beginning with name.
!?name	Search for a command which contain name.

Autocompletion

Autocompletion works with binary, path and env variable. Output is colored upon type. Using arrows to navigate is supported. Autorefreshing with a new input from the user: modification of the list of possibility.

Commands	Functions
$> l[tab]	Search for binary.
$> ls s[tab]	Search for path/files.
$> $[tab]	Search for variables in env.
$> [a-b]{1,2}*[tab]	Search file matching pattern.

Globbing

Posix globbing see Pattern Matching Notation

Pattern	Behavior
*	Everything.
?	Single char.
[a-z]	Match range from a to z.
[!a-z] [^a-z]	Exclude range from a to z.

Job Control

Commands	Functions
jobs	List all the current running jobs.
fg	Bring the most recent process to foreground.
fg n	Bring the specified jobs to foreground where n is the numerical value of the process found in jobs.
Ctrl+C	Terminate/Kill current foreground process.
Ctrl+Z	Suspend/Stop current foreground process.

Variable Expansion

During execution, the shell perform various expansion as specified by POSIX. Our Shell do in order:

commands	Exemple	Functions
• Brace Expansion: a{d,c,b}e	a{d,c,b}e	Expansion of expressions within braces.
• Tilde Expansion:	~	Expansion of the ~ character.
• Shell Parameter Expansion	$PATH, ${PATH}, ${#PATH}	expands local and environement variable.
• Command Substitution	$(ls), `echo a`	Using the output of a command as an argument.
• Word Splitting	$> IFS=a; var=baba echo $var => b b	the result of the three expansions above are splitted into token using IFS variable.
• Filename Expansion	*, [a-z], [!a-z]	match file with shell regex.
• Quote Removal	$>echo "lol" => lol	remove quotes and backslash as needed.

Grammar

Tokens

Bellow the tokens of the POSIX Grammar which can take many litteral forms. In the exemple le token is in ' '.

Tokens	Exemple
WORD	ls './srcs'
ASSIGNMENT_WORD	'a=b' ;
NAME	for 'foo' in bar; do ls; done
NEWLINE	ls '\n' ls
IO_NUMBER	ls ./srcs '2'&>1

Rules

Bellow the Backus Naur form of the POSIX Grammar which we parse and execute.

Symbol	Components
complete_commands	complete_commands newline_list complete_command complete_command
complete_command	list separator_op list
list	list separator_op and_or and_or
and_or	pipeline and_or '&&' linebreak pipeline and_or '
pipeline	pipe_sequence '!' pipe_sequence
pipe_sequence	command pipe_sequence ' ' linebreak command
command	simple_command compound_command compound_command redirect_list function_definition
compound_command	brace_group subshell for_clause case_clause if_clause while_clause until_clause
subshell	'(' compound_list ')'
compound_list	linebreak term linebreak term separator
term	term separator and_or and_or
for_clause	'for' name do_group 'for' name sequential_sep do_group 'for' name linebreak in sequential_sep do_group 'for' name linebreak in wordlist sequential_sep do_group
name	NAME
in	'in'
wordlist	wordlist WORD WORD
case_clause	'case' WORD linebreak in linebreak case_list 'esac' 'case' WORD linebreak in linebreak case_list_ns 'esac' 'case' WORD linebreak in linebreak 'esac'
case_list_ns	case_list case_item_ns case_item_ns
case_list	case_list case_item case_item
case_item_ns	pattern ')' linebreak pattern ')' compound_list '(' pattern ')' linebreak '(' pattern ')' compound_list
case_item	pattern ')' linebreak ';;' linebreak pattern ')' compound_list ';;' linebreak '(' pattern ')' linebreak ';;' linebreak '(' pattern ')' compound_list ';;' linebreak
pattern	WORD
if_clause	'if' compound_list 'then' compound_list else_part 'fi' 'if' compound_list 'then' compound_list 'fi'
else_part	'elif' compound_list 'then' compound_list 'elif' compound_list 'then' compound_list else_part 'else' compound_list
while_clause	'while' compound_list do_group
until_clause	'until' compound_list do_group
function_definition	fname '(' ')' linebreak function_body
function_body	compound_command
fname	NAME
brace_group	'{' compound_list '}'
do_group	'do' compound_list 'do'ne
simple_command	cmd_prefix cmd_word cmd_suffix cmd_prefix cmd_word cmd_prefix cmd_name cmd_suffix cmd_name
cmd_name	WORD
cmd_word	WORD
cmd_prefix	io_redirect cmd_prefix io_redirect ASSIGNMENT_WORD cmd_prefix ASSIGNMENT_WORD
cmd_suffix	io_redirect cmd_suffix io_redirect WORD cmd_suffix WORD
redirect_list	io_redirect redirect_list io_redirect
io_redirect	io_file IO_NUMBER io_file io_here IO_NUMBER io_here
io_file	'<' filename '<&' filename '>' filename '>&' filename '>>' filename '<>' filename '>
filename	WORD
io_here	'<<' here_end '<<-' here_end
here_end	WORD
newline_list	NEWLINE newline_list NEWLINE
linebreak	newline_list
separator_op	'&'
separator	separator_op linebreak newline_list newline_list

Exemples

This code of the factorial function works fine in our shell.

factorial()
{
  if test "$1" -gt "1" ; then
    i=$(($1 - 1))
    j=$(factorial $i)
    k=$(($1 * $j))
    echo $k
  else
    echo 1
  fi
}   

Authors

• COMBEY Vincent - vcombey
• DE SEDE Adrien - ade-sede
• EDDAOUDI Said - github
• DUMOULIN Thibaut - github