Simple_Shell

Table of Content

About
Rules
Checks
Compilation
- Requirements
- How to compile
Samples
Authors

About

This project is an implementation of a simple shell for UNIX-like systems.

It was done in fulfilment of the ALX Software Engineering Programme's syllabus.

Rules

General Rules

All files to be compiled on Ubuntu 20.04 LTS using gcc, using the options -Wall -Werror -Wextra -pedantic -std=gnu89.
Code should use Betty style
Your shell should not have any memory leaks
No more than 5 functions per file
Use system calls only when you need to
All header files should be include-guarded
All files should end with a new line
You should have an AUTHORS file at the root of your repository, listing all individuals having contributed content to the repository.

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]

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)

Checks

✔️ Write a beautiful code that passes the Betty checks
✔️ Handle command lines with arguments
✔️ Handle the PATH
✔️ Implement the exit built-in, that exits the shell
✔️ Write your own getline function
✔️ You are not allowed to use strtok
✔️ Implement the builtin command cd
✔️ Handle variables replacement
✔️ Handle comments (#)
✔️ Your shell can take a file as a command line arguments

Compilation

Requirements

Ubuntu 20.04 LTS
GCC compiler

How to compile

The source files to be compiled using -Wall -Werror -Wextra -pedantic -std=gnu89 flags.

The samples below illustrate the usage and compilation.

Samples

ian@github:~/shell$ gcc -Wall -Werror -Wextra -pedantic -std=gnu89 *.c -o simple_shell
ian@github:~/shell$ ./simple_shell

$ env
USER=ian
LANGUAGE=en_US
SESSION=ubuntu
COMPIZ_CONFIG_PROFILE=ubuntu
SHLVL=1
HOME=/home/ian
C_IS=Fun_:)
DESKTOP_SESSION=ubuntu
LOGNAME=ian
TERM=xterm-256color
PATH=/home/julien/bin:/home/julien/.local/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin
DISPLAY=:0
$ /bin/ls
barbie_j       env-main.c  exec.c  fork.c  pid.c  ppid.c    prompt   prompt.c  shell_0.3  stat    test_scripting.sh  wait.c
env-environ.c  exec    fork    mypid   ppid   printenv  promptc  shell     shell.c    stat.c  wait
$ ls
barbie_j       env-main.c  exec.c  fork.c  pid.c  ppid.c    prompt   prompt.c  shell_0.3  stat    test_scripting.sh  wait.c
env-environ.c  exec    fork    mypid   ppid   printenv  promptc  shell     shell.c    stat.c  wait
$ ls -l /tmp 
total 20
-rw------- 1 julien julien    0 Dec  5 12:09 config-err-aAMZrR
drwx------ 3 root   root   4096 Dec  5 12:09 systemd-private-062a0eca7f2a44349733e78cb4abdff4-colord.service-V7DUzr
drwx------ 3 root   root   4096 Dec  5 12:09 systemd-private-062a0eca7f2a44349733e78cb4abdff4-rtkit-daemon.service-ANGvoV
drwx------ 3 root   root   4096 Dec  5 12:07 systemd-private-062a0eca7f2a44349733e78cb4abdff4-systemd-timesyncd.service-CdXUtH
-rw-rw-r-- 1 julien julien    0 Dec  5 12:09 unity_support_test.0
$ ^C

ian@github:~/shell$

Author(s)

Ian Duncan.

dr8co/simple_shell