This repository contains our own simple version of the shell which is a simple UNIX shell based on bash and Sh. This command line interpreter emulator is written in C language.
it is an application that emulates a shell in mode interactive. this emulator is a sh compatible command language interpreter that executes commands read from standard input.
| File | Description |
|---|---|
| man_1_simple_shell | It is the manual for using the shell. Contains a description, ways for invocation, and some examples of builtins and executables that can be used inside the command line interpreter. |
| shell.c | It contains the entry point of the program, where the execution begins. It shows the prompt and receives the characters written in the command line. |
| main.h | It is a header file that contains all the c libraries needed for the program, the description and prototypes of all the functions, structures, builtins,and printing functions. |
| handler.c | It compare the command with a list of builtins, and if there is a match, It calls the associated builtin. |
| tokenize.c | Save the separate string. it was separated using a delimiter designed to analyze them later. |
| _exit.c | allows the end of the program in a controlled way, controller output. |
Usage: hsh hsh is started with the standard input connected to the terminal. To start, compile all .c located in this repository by using this command:
gcc -Wall -Werror -Wextra -pedantic *.c -o hsh
hsh is allowed to be invoked interactively and non-interactively.
When hsh is invoked with standard input connected to a terminal (determined by isatty(3), the interactive mode is opened.
Usage: hsh
simple_shell$ ./hsh
linux~$
linux~$ ls
README.md shell.c main.h tokens.c ...
linux~$ exit
simple_shell$Example:
$ ./hsh
linux~$ pwd
/home/vagrant/c16/simple_shell
While running in interactive mode, hsh ignores the keyboard input ctrl+c. Alternatively, an input of End-Of-File ctrl+d will exit the program.
User hits ctrl+d in the foutrh command.
$ ./hsh
linux~$ ^C
linux~$ ^C
linux~$
If hsh is invoked with standard input not connected to a terminal, it reads and executes received commands in order. (non-interactively).
$ cat myfile
echo 'hello holberton'
$ ./hsh myfile
'holberton'
$
$ echo "echo $?" | ./hsh
0
Upon invocation, hsh receives and copies the environment of the parent process in which it was executed. This environment is an array of name-value strings describing variables in the format NAME=VALUE. A few key environmental variables are:
The home directory of the current user and the default directory argument for the cd builtin command.
$ echo "echo $HOME" | ./hsh
/home/vagrant
The current working directory as set by the cd command.
$ echo "echo $PWD" | ./hsh
/home/vagrant/c16/simple_shell
| Commands | Description |
|---|---|
ls |
ls (from list), allows you to list the contents of a directory or file. |
pwd |
Pwd (from print working directory) is a convenient command that prints our path or location when executed, so we avoid getting lost if we are working with multiple directories and folders. |
touch |
touch creates an empty file, if the file exists it updates the modification time. |
rm |
rm (from remove) is the command needed to delete a file or directory. |
mkdir |
mkdir (from make directory) creates a new directory taking into account the current location. |
cp |
cp (from copy) copies a source file or directory to a target fileor directory. |
rmdir |
rmdir (from ReMove DIRectory) This command is used to delete empty directories or subdirectories. |
cd |
cd (from change directory) you will need this command to access a path other than the one you are in. basically it is for navigating from directory to directory. |
exit |
exits the current shell. 0 status value indicates successful execution, another value represents unsuccessful execution. |
cat |
cat (from concatenate), is a wonderful utility that allows us to visualize the content of a text file in the standard output, without the need of an editor. |
- Bruno G.: GitHub
- Rogelio : [Not Found] (#)