Shell is a command programming language that executes commands read from a terminal or a file.
Shell was developed and tested on Ubuntu 14.04 LTS via Vagrant in VirtualBox.
File Contents The repository contains the following files:
| File | Description |
|---|---|
| main.c | The main function |
| atoi.c | Converts a string to an integer |
| AUTHORS | Contains info about authors of the project |
| builtins.c | Handles exit, cd and env built-in commands |
| ctrl.c | Actions for when Ctrl+D and Ctrl+C is entered into the shell |
| executeprog.c | Containing function, that execute a line of code in the shell as well as a function that checks for build-ins |
| holberton.h | Header file containing all function prototypes and struct declarations |
| _freeops.c | Freeing all varibles used as well as tokens in a tokenarray and a linked list |
| _getenv.c | Looks at environment variable and returns a pointer to string that matches |
| man_1_simple_shell | Man page for the created shell |
| no_file.c | Write an error message, if file not found |
| path_handler.c | Iterates through PATH variable and concatinates command into it |
| _realloc.c | Reallocates memory for an array |
| _strops.c | Contains functions needed for the string manipulations |
| tokensplit.c | Splits a line into tokens and stores into a char* array |
| _llops.c | functions for creating an empty linked list and filling it with the contents of the $PATH variable |
| Function | Description |
|---|---|
| void printprompt(void) | prints the $ prompt at every new loop iteration |
| int _strlen(char *buf) | Calculates the length of the string |
| int _strcmp(char *s1, char *s2) | compares two strings |
| char *_strdup(char *str) | returns pointer to allocated space containing copy of string |
| char *str_concat(char *s1, char *s2) | contatenates two strings |
| char *_concat(char *concatenate, char *s1, char *s2) | concatenates two strings |
| int _atoi(char *s) | converts a string to an integer |
| char *printint(int num) | converts an integer to a string |
| path_t *create_ll(char *str) | creates an empty linked list the size of the $PATH variable |
| path_t *fill_list(char *str, path_t *list) | fills an empty linked list with PATH variable contents |
| void free_list(path_t *head) | frees a path_t list |
| void free_tokens(char **tokenarray) | frees the tokens in the tokenarray |
| void free_all(char *line, char *newline, char **tokenarray) | frees all of the variables used |
| int ctrld(char *line) | actions for when Ctrl+D is entered into the shell |
| void ctrlc(int signum) | Ctrl+C handler (ie does not exit when SIGINT is sent |
| void no_file_er(char **argv, char **ar, int cmdnum, char *line, char *nline) | write an error message if file is not found |
| int exit_op(char **array, char *line, char *newline) | handles exit builin |
| int cd_op(char **array, char **env) | handles the cd builtin |
| int env_op(char **env) | handles env builtin |
| char **tokensplit(char *line) | splits a line into tokens and stores into a char* array |
| int exec(char **ar, char **env, char **av, char *line, char *nline, int cdnum) | executes a line of code in the shell |
| char *_getenv(const char *name, char **env) | looks at enviroment variable and returns a pointer to string |
| char **_realloccharss(char **ptr, int n) | reallocates memory for char** |
| char *_reallocchar(char *ptr) | reallocates memory for char* |
| char *path_handler(char *str, char **env) | iterates through $PATH variable end concatenates command into it |
Clone the repository, compile with compilation flags, listed below, then run the executable.
$ git clone https://github.com/dkwok94/simple_shell.git
This code was compiled this way:
$ gcc -Wall -Werror -Wextra -pedantic *.c -o hsh
int main(int ac, char **av, char **env)
{
(void)ac, (void)av;
char *line, *newline;
size_t len;
ssize_t characters = 0;
char **tokenarray;
while (1)
{
line = NULL;
len = 0;
if (isatty(STDIN_FILENO) == 1)
{
write(STDOUT_FILENO, "$ ", 2);
signal(SIGINT, ctrlc);
}
characters = getline(&line, &len, stdin);
if (line[0] == '\n')
{
free(line);
continue;
}
if (characters == EOF)
return (ctrld(line));
newline = _reallocchar(line);
tokenarray = tokensplit(newline);
if (tokenarray == NULL)
{
free(line);
return (0);
}
executeprog(tokenarray, env, av);
free_all(line, newline, tokenarray);
}
free(line);
return (0);
}
vagrant@vagrant-ubuntu-trusty-64:~/holbertonschool-low_level_programming/shelll$ ./hsh
$ ls
#README.md# _getline.c~ build_ins.c holberton.h no_file.c test_results
README.md _llops.c build_ins.c~ hsh path_handler.c tokensplit.c
_freeops.c _realloc.c builtins.c main.c preparation_functions
_getenv.c _strops.c ctrl.c man_shell shelltest
_getline.c atoi.c executeprog.c man_shell~ test_2
$
vagrant:simple_shell$ ./hsh
$ pwd
/home/vagrant/simple_shell
$
vagrant@vagrant-ubuntu-trusty-64:~/holbertonschool-low_level_programming/shelll$ ./hsh
$ env
XDG_SESSION_ID=2
TERM=cygwin
SHELL=/bin/bash
SSH_CLIENT=10.0.2.2 60471 22
SSH_TTY=/dev/pts/0
USER=vagrant
LS_COLORS=rs=0:di=01;34:ln=01;36:mh=00:pi=40;33:so=01;35:do=01;35:bd=40;33;01:cd=40;33;01:or=40;31;01:su=37;41:sg=30;43:ca=30;41:tw=30;42:ow=34;42:st=37;44:ex=01;32:*.tar=01;31:*.tgz=01;31:*.arj=01;31:*.taz=01;31:*.lzh=01;31:*.lzma=01;31:*.tlz=01;31:*.txz=01;31:*.zip=01;31:*.z=01;31:*.Z=01;31:*.dz=01;31:*.gz=01;31:*.lz=01;31:*.xz=01;31:*.bz2=01;31:*.bz=01;31:*.tbz=01;31:*.tbz2=01;31:*.tz=01;31:*.deb=01;31:*.rpm=01;31:*.jar=01;31:*.war=01;31:*.ear=01;31:*.sar=01;31:*.rar=01;31:*.ace=01;31:*.zoo=01;31:*.cpio=01;31:*.7z=01;31:*.rz=01;31:*.jpg=01;35:*.jpeg=01;35:*.gif=01;35:*.bmp=01;35:*.pbm=01;35:*.pgm=01;35:*.ppm=01;35:*.tga=01;35:*.xbm=01;35:*.xpm=01;35:*.tif=01;35:*.tiff=01;35:*.png=01;35:*.svg=01;35:*.svgz=01;35:*.mng=01;35:*.pcx=01;35:*.mov=01;35:*.mpg=01;35:*.mpeg=01;35:*.m2v=01;35:*.mkv=01;35:*.webm=01;35:*.ogm=01;35:*.mp4=01;35:*.m4v=01;35:*.mp4v=01;35:*.vob=01;35:*.qt=01;35:*.nuv=01;35:*.wmv=01;35:*.asf=01;35:*.rm=01;35:*.rmvb=01;35:*.flc=01;35:*.avi=01;35:*.fli=01;35:*.flv=01;35:*.gl=01;35:*.dl=01;35:*.xcf=01;35:*.xwd=01;35:*.yuv=01;35:*.cgm=01;35:*.emf=01;35:*.axv=01;35:*.anx=01;35:*.ogv=01;35:*.ogx=01;35:*.aac=00;36:*.au=00;36:*.flac=00;36:*.mid=00;36:*.midi=00;36:*.mka=00;36:*.mp3=00;36:*.mpc=00;36:*.ogg=00;36:*.ra=00;36:*.wav=00;36:*.axa=00;36:*.oga=00;36:*.spx=00;36:*.xspf=00;36:
MAIL=/var/mail/vagrant
PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games
PWD=/home/vagrant/simple_shell
LANG=en_US.UTF-8
SHLVL=1
HOME=/home/vagrant
LOGNAME=vagrant
SSH_CONNECTION=10.0.2.2 60471 10.0.2.15 22
LESSOPEN=| /usr/bin/lesspipe %s
XDG_RUNTIME_DIR=/run/user/1000
LESSCLOSE=/usr/bin/lesspipe %s %s
OLDPWD=/home/vagrant
_=./hsh
$
Derek Kwok, Elena Serebryakova