- 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
$
Some error with your program
$ echo "qwerty" | ./hsh
./hsh: 1: qwerty: not found
$ echo "qwerty" | ./././hsh
./././hsh: 1: qwerty: not found
$
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)
Your shel will be compiled this way:
gcc -Wall -Werror -Wextra -pedantic -std=gnu89 *.c -o hsh
Your shell should work like this in interactive mode:
$ ./hsh
($) /bin/ls
hsh main.c shell.c
($)
($) exit
$```
But also in non-interactive mode:
```shell
$ 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
$
The Checker will be released at the end of the project (1-2 days before the deadline). We strongly encourage the entire class to work together to create a suite of checks covering both regular tests and edge cases for each task. See task 8. Test suite
.
Write a beautiful code that passes the Betty checks
Repo:
- GitHub repository:
simple_shell
Write a UNIX command line interpreter.
-
Usage:
simple_shell
Your Shell should:-
Display a prompt and wait for the user to type a command. A command line always ends with a new line.
-
The prompt is displayed again each time a command has been executed.
-
The command lines are simple, no semicolons, no pipes, no redirections or any other advanced features.
-
The command lines are made only of one word. No arguments will be passed to programs.
-
If an executable cannot be found, print an error message and display the prompt again.
-
Handle errors.
-
You have to handle the “end of file” condition (
Ctrl+D
) You don’t have to: -
use the
PATH
-
implement built-ins
-
handle special characters :
"
,'
,,
`,*
,&
,#
-
be able to move the cursor
-
handle commands with arguments
-
execve
will be the core part of your Shell, don’t forget to pass the environ to it…
julien@ubuntu:~/shell$ ./shell
#cisfun$ ls
./shell: No such file or directory
#cisfun$ /bin/ls
barbie_j env-main.c exec.c fork.c pid.c ppid.c prompt prompt.c shell.c stat.c wait
env-environ.c exec fork mypid ppid printenv promptc shell stat test_scripting.sh wait.c
#cisfun$ /bin/ls -l
./shell: No such file or directory
#cisfun$ ^[[D^[[D^[[D
./shell: No such file or directory
#cisfun$ ^[[C^[[C^[[C^[[C
./shell: No such file or directory
#cisfun$ exit
./shell: No such file or directory
#cisfun$ ^C
julien@ubuntu:~/shell$ echo "/bin/ls" | ./shell
barbie_j env-main.c exec.c fork.c pid.c ppid.c prompt prompt.c shell.c stat.c wait
env-environ.c exec fork mypid ppid printenv promptc shell stat test_scripting.sh wait.c
#cisfun$ julien@ubuntu:~/shell$
Repo:
- GitHub repository:
simple_shell
Simple shell 0.1 +
-
Handle command lines with arguments Repo:
-
GitHub repository:
simple_shell
Simple shell 0.2 +
- Handle the
PATH
fork
must not be called if the command doesn’t exist
julien@ubuntu:~/shell$ ./shell_0.3
:) /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
julien@ubuntu:~/shell$
Repo:
- GitHub repository:
simple_shell
Simple shell 0.3 +
-
Implement the
exit
built-in, that exits the shell -
Usage:
exit
-
You don’t have to handle any argument to the built-in
exit
Repo: -
GitHub repository:
simple_shell
Simple shell 0.4 +
- Implement the
env
built-in, that prints the current environment
julien@ubuntu:~/shell$ ./simple_shell
$ env
USER=julien
LANGUAGE=en_US
SESSION=ubuntu
COMPIZ_CONFIG_PROFILE=ubuntu
SHLVL=1
HOME=/home/julien
C_IS=Fun_:)
DESKTOP_SESSION=ubuntu
LOGNAME=julien
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
$ exit
julien@ubuntu:~/shell$
Repo:
- GitHub repository:
simple_shell
Simple shell 0.1 +
- Write your own
getline
function - Use a buffer to read many chars at once and call the least possible the
read
system call - You will need to use
static
variables - You are not allowed to use
getline
You don’t have to:
-
be able to move the cursor Repo:
-
GitHub repository:
simple_shell
Simple shell 0.2 +
You are not allowed to use strtok
Repo:
- GitHub repository:
simple_shell
Simple shell 0.4 +
- handle arguments for the built-in
exit
- Usage:
exit status
, where status is an integer used toexit
the shell
julien@ubuntu:~/shell$ ./shell_0.4.1
$ exit 98
julien@ubuntu:~/shell$ echo $?
98
julien@ubuntu:~/shell$
Repo:
- GitHub repository:
simple_shell
Simple shell 1.0 +
Implement the setenv
and unsetenv
builtin commands
-setenv
- Initialize a new environment variable, or modify an existing one
- Command syntax: setenv VARIABLE VALUE
- Should print something on stderr on failure
-
unsetenv
- Remove an environment variable
- Command syntax: unsetenv VARIABLE
- Should print something on stderr on failure Repo:
-
GitHub repository:
simple_shell
Simple shell 1.0 +
Implement the builtin command cd
:
-
Changes the current directory of the process.
-
Command syntax:
cd [DIRECTORY]
-
If no argument is given to cd the command must be interpreted like
cd $HOME
-
You have to handle the command
cd -
-
You have to update the environment variable
PWD
when you change directoryman chdir
,man getcwd
Repo: -
GitHub repository:
simple_shell
Simple shell 1.0 +
- Handle the commands separator
;
alex@~$ ls /var ; ls /var
backups cache crash lib local lock log mail metrics opt run spool tmp
backups cache crash lib local lock log mail metrics opt run spool tmp
alex@~$ ls /hbtn ; ls /var
ls: cannot access /hbtn: No such file or directory
backups cache crash lib local lock log mail metrics opt run spool tmp
alex@~$ ls /var ; ls /hbtn
backups cache crash lib local lock log mail metrics opt run spool tmp
ls: cannot access /hbtn: No such file or directory
alex@~$ ls /var ; ls /hbtn ; ls /var ; ls /var
backups cache crash lib local lock log mail metrics opt run spool tmp
ls: cannot access /hbtn: No such file or directory
backups cache crash lib local lock log mail metrics opt run spool tmp
backups cache crash lib local lock log mail metrics opt run spool tmp
alex@~$
Repo:
- GitHub repository:
simple_shell
Simple shell 1.0 +
- Handle the
&&
and||
shell logical operators
alex@~$ ls /var && ls /var
backups cache crash lib local lock log mail metrics opt run spool tmp
backups cache crash lib local lock log mail metrics opt run spool tmp
alex@~$ ls /hbtn && ls /var
ls: cannot access /hbtn: No such file or directory
alex@~$ ls /var && ls /var && ls /var && ls /hbtn
backups cache crash lib local lock log mail metrics opt run spool tmp
backups cache crash lib local lock log mail metrics opt run spool tmp
backups cache crash lib local lock log mail metrics opt run spool tmp
ls: cannot access /hbtn: No such file or directory
alex@~$ ls /var && ls /var && ls /var && ls /hbtn && ls /hbtn
backups cache crash lib local lock log mail metrics opt run spool tmp
backups cache crash lib local lock log mail metrics opt run spool tmp
backups cache crash lib local lock log mail metrics opt run spool tmp
ls: cannot access /hbtn: No such file or directory
alex@~$
alex@~$ ls /var || ls /var
backups cache crash lib local lock log mail metrics opt run spool tmp
alex@~$ ls /hbtn || ls /var
ls: cannot access /hbtn: No such file or directory
backups cache crash lib local lock log mail metrics opt run spool tmp
alex@~$ ls /hbtn || ls /hbtn || ls /hbtn || ls /var
ls: cannot access /hbtn: No such file or directory
ls: cannot access /hbtn: No such file or directory
ls: cannot access /hbtn: No such file or directory
backups cache crash lib local lock log mail metrics opt run spool tmp
alex@~$ ls /hbtn || ls /hbtn || ls /hbtn || ls /var || ls /var
ls: cannot access /hbtn: No such file or directory
ls: cannot access /hbtn: No such file or directory
ls: cannot access /hbtn: No such file or directory
backups cache crash lib local lock log mail metrics opt run spool tmp
alex@~$
Repo:
- GitHub repository:
simple_shell
Simple shell 1.0 +
Implement the alias
builtin command
Usage: alias [name[='value'] ...]
- alias
: Prints a list of all aliases, one per line, in the form name='value'
- alias name [name2 ...]
: Prints the aliases name
, name2
, etc 1 per line, in the form name='value'
-alias name='value' [...]
: Defines an alias for each name
whose value
is given. If name
is already an alias, replaces its value with value
Repo:
- GitHub repository:
simple_shell
Simple shell 1.0 +
- Handle variables replacement
- Handle the
$?
variable - Handle the
$$
variable
julien@ubuntu:~/shell$ ./hsh
$ ls /var
backups cache crash lib local lock log mail metrics opt run snap spool tmp
$ echo $?
0
$ echo $$
5104
$ echo $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
$ exit
julien@ubuntu:~/shell$
Repo:
- GitHub repository:
simple_shell
Simple shell 1.0 +
Handle comments (#
)
julien@ubuntu:~/shell$ sh
$ echo $$ # ls -la
5114
$ exit
julien@ubuntu:~/shell$
Repo:
- GitHub repository:
simple_shell
Simple shell 1.0 +
-
Usage:
simple_shell [filename]
-
Your shell can take a file as a command line argument
-
The file contains all the commands that your shell should run before exiting
-
The file should contain one command per line
-
In this mode, the shell should not print a prompt and should not read from
stdin
Repo: -
GitHub repository:
simple_shell
You can try our shell by following these steps:
Step 1: Clone our repository using this command, (you need to have git installed on your machine first)
git clone https://github.com/MatriMariem/simple_shell
Step 2: Change directory to simple_shell:
cd simple_shell
Step 3: Compile the C files in this way:
gcc -Wall -Werror -Wextra -pedantic *.c -o hsh
Step 4: Run the shell
./hsh
Exiting the shell When you want to exit the shell, you can use one of the following methods:
1: Type the command "exit"
exit
2: Press on Ctrl + D