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https://github.com/johnnieshere/shell-program

This is a simple shell program written in C for Linux-based machines. It reads commands from the user or a script file, executes them, and handles special commands like "alias", "unalias", and "source". It also counts the number of commands, script lines, and commands that contains quotes. It uses a stack to check for quotes in the input.
https://github.com/johnnieshere/shell-program

linux linux-shell-implementation linux-shell-in-c

Last synced: 30 days ago
JSON representation

Host: GitHub
URL: https://github.com/johnnieshere/shell-program
Owner: JohnniesHere
License: mit
Created: 2024-06-05T09:15:26.000Z (7 months ago)
Default Branch: main
Last Pushed: 2024-07-04T10:26:31.000Z (6 months ago)
Last Synced: 2024-10-16T19:38:30.079Z (3 months ago)
Topics: linux, linux-shell-implementation, linux-shell-in-c
Language: C
Homepage:
Size: 49.8 KB
Stars: 0
Watchers: 1
Forks: 0
Open Issues: 0
Metadata Files:
- Readme: README.md

Awesome Lists containing this project

README

Authorize: Jonathan Elgarisi

## Shell Program
This is a simple shell program written in C for Linux-based machines. It reads commands from the user or a script file,
executes them, and handles special commands like \"alias\", \"unalias\",
and \"source\". It also counts the number of commands, script lines, and
commands that contains quotes. It uses a stack to check for quotes in
the input.

## Features
- Execute commands from user input or a script file.
-Handle special commands: \"alias\", \"unalias\", and \"source\".
- Count the number of commands, script lines, and commands that contain
quotes. - Check for matching quotes in the input using a stack.
- Support for && and \|\| operators.
- Support for & operator.
- Support for 2\> operator.
- Support for jobs command.

## How to Run
To compile the program, use the following command:
```bash
#!/bin/bash gcc -Wall ex1.c -o ex1
```
Or use the run_me.sh script file as an alternative to compiling it
yourself.

## How to Use
After succesfully launching the script or the command
lines provided above you can enter Linux commands or using one of the
special commands.

*Special Commands:
-alias: creates a shortcut for a command in the
format alias \=\'\\' and will save it in a linked-list
strcture.
In order to see the aliases list enter the word alias.
```bash
alias ll='ls -l' #will assaign ll as a shortcut for the command ls -l. then, typing alias will result with the output: ll='ls -l'
```

-unalias: to remove a shortcut from the aliases list
```bash
unalias ll #will remove the shortcut ll from the aliases linked-list)
```
-source: running script files, in order to use this command enter this format source
```bash
source script.sh will run the script.sh file located at the same folder as this shell)
```
-exit_shell: closes the shell program and prints the number of commands
that contained quotes.

-jobs: displays all processes running in the background.
Example:
```bash
sleep 50 &
sleep 50 &
sleep 50 &
#Starts 3 background processes.
```

```bash
jobs #Shows all running background processes with their PIDs.
[1] sleep 50 &
[2] sleep 50 &
[3] sleep 50 &
```

## Additional Features:
- && and || operators: These operators allow conditional execution of commands.
- &&: Command2 will run only if Command1 successfully executed.
- ||: Command2 will run only if Command1 failed to execute.
Example:
```
asdf && ls #asdf is not a valid command, so ls will not be executed.
asdf || ls asdf is not a valid command, so ls will be executed.
```

& operator: The & character at the end of a command will run the command in the background, allowing the user to run more commands immediately.
Example:
```bash
sleep 5 #Runs sleep for 5 seconds, and the shell is "stuck" during this time.
sleep 5 & #Runs sleep for 5 seconds in the background, allowing immediate command input.
```

2> operator: Redirects error output (stderr) to a file.
Example:
```bash
command 2> error_log #Runs the command, writing any error messages to the file error_log.
aaaa 2\> E #aaaa is not a valid command, so its error message is written to E. cat E will print the error message from the file.
(aaa && ls) 2\> EE #If aaa is invalid, its error message is written to EE, and ls will not be executed.
```
## Output
According to your commands.
Errors will be provide information if occurs.

## Files
- ex1.c: The main file containing the shell program.
- Stack.h: Contains the definition and functions for a stack data structure used for checking matching quotes.
- Alias.h: Contains the definition and functions for handling command aliases.
- Jobs.h: Contains the definition and functions for handling background jobs.
- runData.h: Contains the definition for tracking script lines and quote counts.
- run_me.sh: A script file to run the shell program.
- README.txt: The text file you\'re currently reading.

## License
MIT- https://choosealicense.com/licenses/mit/