/minishell

As beautiful as a shell :shell:

Primary LanguageCMIT LicenseMIT

minishell

As beautiful as a shell

introduction

The objective of this project is to create a simple shell and learn a lot about processes and file descriptors

The existence of shells is linked to the very existence of IT. At the time, all coders agreed that communicating with a computer using aligned 1/0 switches was seriously irritating. It was only logical that they came up with the idea to communicate with a computer using interactive lines of commands in a language somewhat close to english. With Minishell project, we’ll be able to travel through time and come back to problems people faced when Windows didn’t exist.

image

usage

Clone the repo git clone --recurse-submodules https://github.com/paulahemsi/minishell.git

Install Readline library make install

Compile Minishell make

Run ./minishell

Enjoy!

minihell_2x

builtins_implemented

command description
echo echo the STRING(s) to standart output. -n flag: do not output the trailing newline
cd change the shell working directory (with a relative or absolute path)
pwd print name of current/working directory
export set export attribute for shell variables
unset unset values of shell variables
env print the environment
exit cause the shell to exit with the exit status specified

step_by_step

  • Prompt implementation
  • HashTable functions implementation
  • Tokenizer implementation
  • Variables expansion implementation
  • Builtins implementation
  • Parse and execute sistem design
  • Signals implementation
  • Parsing implementation
  • Execute implementation
  • Norme
  • Bugs hunting

mindmap

mindmap

study_resources

unix

hashtable

tokenizer

more

libft_functions

Click to expand

Part_1

ctype.h

Function Description
ft_isalpha checks for an alphabetic character.
ft_isdigit checks for a digit (0 through 9).
ft_isalnum checks for an alphanumeric character; it is equivalent to (isalpha(c)
ft_isascii checks whether c is a 7-bit unsigned char value that fits into the ASCII character set.
ft_isprint checks for any printable character including space.
ft_isupper checks if character is uppercase.
ft_toupper convert lowercase letters to uppercase
ft_tolower convert uppercase letters to lowercase.

string.h

Function Description
ft_memset fills the first n bytes of the memory area pointed to by s with the constant byte c
ft_bzero erases the data in the n bytes of the memory starting at the location pointed to by s, by writing zeros (bytes containing '\0') to that area.
ft_memcpy copies n bytes from memory area src to memory area dest. The memory areas must not overlap. Use memmove(3) if the memory areas do overlap.
ft_memccpy copies no more than n bytes from memory area src to memory area dest, stopping when the character c is found. If the memory areas overlap, the results are undefined.
ft_memmove copies n bytes from memory area src to memory area dest. The two strings may overlap; the copy is always done in a non-destructive manner.
ft_memchr scans the initial n bytes of the memory area pointed to by s for the first instance of c.
ft_memcmp function compares the first n bytes (each interpreted as unsigned char) of the memory areas s1 and s2.
ft_strlen The ft_strlen() function computes and returns the length of the string s.
ft_strlcpy copies up to size - 1 characters from the NUL-terminated string src to dst, NUL-terminating the result.
ft_strlcat appends the NUL-terminated string src to the end of dst. It will append at most size - strlen(dst) - 1 bytes, NUL-terminating the result.
ft_strchr returns a pointer to the first occurrence of the character c in the string s.
ft_strrchr returns a pointer to the last occurrence of the character c in the string s.
ft_strnstr locates the first occurrence of the null-terminated string little in the string big, where not more than len characters are searched.
ft_strncmp lexicographically compares the null-terminated strings s1 and s2. Returns an integer greater than, equal to, or less than 0, according as the string s1 is greater than, equal to, or less than the string s2. Compares not more than n characters. The comparison is done using unsigned characters, so that '\200' is greater than '\0'.
ft_strdup returns a pointer to a new string which is a duplicate of the string s.

stdlib.h

Function Description
ft_atoi converts the initial portion of the string pointed to by str to int representation and returns the int.
ft_calloc allocates memory for an array of nmemb elements of size bytes each and returns a pointer to the allocated memory. The memory is set to zero.

Part_2

string's functions

Function Description
ft_substr Allocates and returns a substring from the string ’s’. The substring begins at index ’start’ and is of maximum size ’len’.
ft_strjoin Allocates and returns a new string, which is the result of the concatenation of ’s1’ and ’s2’.
ft_strtrim Allocates and returns a copy of ’s1’ with the characters specified in ’set’ removed from the beginning and the end of the string.
ft_split Allocates and returns an array of strings obtained by splitting ’s’ using the character ’c’ as a delimiter.
ft_strmapi Applies the function ’f’ to each character of the string ’s’ to create a new string resulting from successive applications of ’f’.

string to int

Function Description
ft_itoa Allocates and returns a string representing the integer received as an argument. Negative numbers must be handled.

file-descriptor's functions

Function Description
ft_putchar_fd Outputs the character ’c’ to the given file descriptor.
ft_putstr_fd Outputs the string ’s’ to the given file descriptor.
ft_putendl_fd Outputs the string ’s’ to the given file descriptor, followed by a newline.
ft_putnbr_fd Outputs the integer ’n’ to the given file descriptor.

Bonus

Linked Lists

Function Description
ft_lstnew Allocates and returns a new element. The variable ’content’ is initialized with the value of the parameter ’content’. The variable ’next’ is initialized to NULL.
ft_lstadd_front Adds the element ’new’ at the beginning of the list.
ft_lstsize Counts the number of elements in a list.
ft_lstlast Returns the last element of the list.
ft_lstadd_back Adds the element ’new’ at the end of the list.
ft_lstdelone Takes as a parameter an element and frees the memory of the element’s content using the function ’del’ given as a parameter and free the element.
ft_lstclear Deletes and frees the given element and every successor of that element, using the function ’del’ and free. Finally, the pointer to the list is set to NULL.
ft_lstiter Iterates the list ’lst’ and applies the function ’f’ to the content of each element.
ft_lstmap Iterates the list ’lst’ and applies the function ’f’ to the content of each element. Creates a new list resulting of the successive applications of the function ’f’. The ’del’ function is used to delete the content of an element if needed.

Double Linked Lists

Function Description
ft_dlstnew Allocates and returns a new element. The variable ’content’ is initialized with the value of the parameter ’content’. The variable ’next’ is initialized to NULL.
ft_dlstadd_front Adds the element ’new’ at the beginning of the double linked list.
ft_dlstsize Counts the number of elements in a double linked list.
ft_dlstlast Returns the last element of the double linked list.
ft_dlstadd_back Adds the element ’new’ at the end of the double linked list.
ft_dlstdelone Takes as a parameter an element and frees the memory of the element’s content using the function ’del’ given as a parameter and free the element.
ft_dlstclear Deletes and frees the given element and every successor of that element, using the function ’del’ and free. Finally, the pointer to the double linked list is set to NULL.
ft_dlstiter Iterates the double linked list ’lst’ and applies the function ’f’ to the content of each element.
ft_dlstmap Iterates the double linked list ’lst’ and applies the function ’f’ to the content of each element. Creates a new double linked list resulting of the successive applications of the function ’f’. The ’del’ function is used to delete the content of an element if needed.

Extras

Function Description
ft_putchar outputs the character c to the standard output.
ft_putstr outputs a string to the standard output.
ft_putendl outputs a string to the standard output, followed by a newline.
ft_putnbr outputs the integer n to the standard output
ft_strequ lexicographical comparison between s1 and s2. If the 2 strings are identical the function returns 1, or 0 otherwise.
ft_strnequ lexicographical comparison between s1 and s2. If the 2 strings are identical the function returns 1, or 0 otherwise.
ft_strclr sets every character of the string s to '\0'.
ft_isspace tests for the white-space characters. For any locale, this includes the following standard characters: \v \n \t \r \f. Returns zero if the character tests false and returns non-zero if the character tests true.
ft_isblank checks for a blank character; that is, a space or a tab.
ft_isxdigit checks for hexadecimal digits.
ft_isnegative checks if a number is negative.
ft_countdigit Count the digits from an unsigned int.
ft_numlen Count the digits from an int.
get_next_line Read a line from stdin or fd
get_next_line_multifd Read a line from multiples fd's
ft_add variadic function which returns the sum of the numbers passed as arguments. The first argument must be the amount of numbers to be summed.
ft_itoa_hex Convert the decimal unsigned integer received as argument to hexadecimal. Allocates and returns a string with the hex number.
ft_putnbr_unsigned outputs the unsigned integer n to the standard output.
ft_free_and_null frees and null the given pointer.

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