0x16. C - Simple Shell Project

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The Gates of Shell by Spencer Cheng, featuring Julien Barbier

Resource

Description

In this project we are tasked with creating our own simple UNIX command interpreter. The program must have the exact same output as sh (/bin/sh) as well as the exact same error output. The only difference is when you print an error, the name of the program must be equivalent to your argv[0].

Instructions

Compiling the program: gcc -Wall -Werror -Wextra -pedantic *.c -o hsh
Interactive mode:

$ ./hsh
($) /bin/ls
hsh main.c shell.c
($)
($) exit
$

Non-interactie mode:

$ echo "/bin/ls" | ./hsh
hsh main.c shell.c test_ls_2
$
$ cat test_ls_2
/bin/ls
/bin/ls
$
$ cat test_ls_2 | ./hsh
hsh main.c shell.c test_ls_2
hsh main.c shell.c test_ls_2
$

Project Requirements

All your files will be compiled on Ubuntu 14.04 LTS
Your C programs and functions will be compiled with gcc 4.8.4 using the flags -Wall -Werror -Wextra and -pedantic
All your files should end with a new line
A README.md file, at the root of the folder of the project is mandatory
Your code should use the Betty style. It will be checked using betty-style.pl and betty-doc.pl
No more than 5 functions per file
All your header files should be include guarded
Use system calls only when you need to

List of allowed functions and system calls

access (man 2 access)
chdir (man 2 chdir)
close (man 2 close)
closedir (man 3 closedir)
execve (man 2 execve)
exit (man 3 exit)
\_exit (man 2 _exit)
fflush (man 3 fflush)
fork (man 2 fork)
free(man 3 free)
getcwd (man 3 getcwd)
getline (man 3 getline)
getpid (man 2 getpid)
isatty (man 3 isatty)
kill (man 2 kill)
malloc (man 3 malloc)
open (man 2 open)
opendir (man 3 opendir)
perror (man 3 perror)
read (man 2 read)
readdir (man 3 readdir)
signal (man 2 signal)
stat (__xstat) (man 2 stat)
lstat (__lxstat) (man 2 lstat)
fstat (__fxstat) (man 2 fstat)
strtok (man 3 strtok)
wait (man 2 wait)
waitpid (man 2 waitpid)
wait3 (man 2 wait3)
wait4 (man 2 wait4)
write (man 2 write)

The shell will be compiled this way:

$ gcc -Wall -Werror -Wextra -pedantic -std=gnu89 \*.c -o hsh

Output

Unless specified otherwise, your program must have the exact same output as sh (/bin/sh) as well as the exact same error output.
The only difference is when you print an error, the name of the program must be equivalent to your argv[0] (see below)

Example of error with sh:

$ echo "qwerty" | /bin/sh
/bin/sh: 1: qwerty: not found
$ echo "qwerty" | /bin/../bin/sh
/bin/../bin/sh: 1: qwerty: not found
$

Same error with your program hsh:

$ echo "qwerty" | ./hsh
./hsh: 1: qwerty: not found
$ echo "qwerty" | ./././hsh
./././hsh: 1: qwerty: not found
$

Testing

The shell should work like this in interactive mode:

$ ./hsh
($) /bin/ls
hsh main.c shell.c
($)
($) exit
$

But also in non-interactive mode:

$ echo "/bin/ls" | ./hsh
hsh main.c shell.c test\_ls\_2
$
$ cat test\_ls\_2
/bin/ls
/bin/ls
$
$ cat test\_ls\_2 | ./hsh
hsh main.c shell.c test\_ls\_2
hsh main.c shell.c test\_ls\_2
$

Authors

Charles Obimnaeto Egesionu :: IamNaeto
Jane Nginika :: Nginika

Acknowledgments

Our fellow cohort members.
The creators of the C language.
Our software engineer-in-residence.
Betty, Alx Holberton.

IamNaeto/simple_shell