BB-SHELL [BBSH ] (V2.0 )

Made for an assignment/s for OS&N Course Monsoon 2022-23.

Completely coded in C.

Build & Run

1. make / make bbsh (For building the executable file)
2. make clean (For cleaning the built files)

ABOUT

BB-SHELL is a very advanced noob shell, which can do some work, but very limited. 😅

It has some of the following features as of now:- (More may not come later)

• Colourful shell display with username/hostname and current directory.
• Can run some built-in commands such as cd, echo, pwd, ls (With -a and -l flags).
• Other Commands - pinfo (≈ ps), discover (≈ find with -d and -f flags)
• Stores history of upto 20, for all the sessions.
• Error Handling
• Can run both background qand foreground processes. (For any other shell commands)
• Multiple Command Execution in a single line using ;.
• exit is used to exit the shell.
• I/O Redirection using pipes and < & >/>>.
• Autocomplete file names.
• Signal Handling (Ctrl-C, Ctrl-Z, Ctrl-D)

OTHER COMMANDS & INSTRUCTIONS

• cd

  Usage: cd <path_to_directory>
  

  Supports the following wildcards:

  • ~ : path to shell's home directory
  • - : path to previous directory
  • . : path to current directory
  • .. : path to parent directory

• pwd

  Usage: pwd
  

• echo

  Usage: echo <string>
  

• ls

  Usage: ls <path_to_directory_1> <path_to_directory_2> ...
  

  Flags:-

  • -a: do not ignore entries starting with .
  • -l: use a long listing format

  Supports all the wildcards as cd.

• pinfo

  Usage: pinfo <pid>
  

  Gives the following info:

  • Process ID
  • Process Status
  • Virtual Memory
  • Path to Executable

• discover

  Usage: discover <target_dir> "<file_name>"
  

  Flags:-

  • -d: searches for all directories
  • -f: searches for all files

  All arguments/flags are optional to use.

• exit

  Usage: exit
  

  Alaias for exit -> quit

• history

  Usage: history
  

  Prints the last 10 commands in the history.

• jobs

  Usage: jobs
  

  • Prints a list of all currently running background processes spawned by the shell in alphabetical order of the command names.

• sig

  Usage: sig <job id> <signal number>
  

  • Sends a signal to the job with given id (Running in background)

• fg

  Usage: fg <job id>
  

  • Brings the process into foreground and set it running.

• bg

  Usage: bg <job id>
  

  • Sets the given id background process in running state.

• <command>

  • Runs the command in the foreground.
  • If & is added at the end, will run the command in background.

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FOR DEVELOPERS

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FILES

1. main.c -> Containing the parent code to run the shell. Just mainly calling different functions.
2. libraries.h -> Containing all the imports and in general definitions.
3. input.c and input.h -> Containing the functions to take input, process it and do tasks based on that. Also, handles the I/O Redirection processes.
4. raw_input.c -> Containing the functions to take raw input, also handling the autocomplete functionality.
5. print.c and print.h -> Containing the code to print prompt, errors, etc.
6. signals.c and signals.h -> Containing the functions to handle different basic signals and process them accordingly.
7. path.c and path.h -> Containing the functions to process different directories and paths.
8. history.c and history.h -> Reading, Processing and Writing History. If want to change the path of the history file, you can use this history.h file.
9. discovery.c and discovery.h -> Handles the code for discovery command and its variants.
10. jobpool.c and jobpool.h -> Manages the current running processes in the shell, along with doing book-keeping for the background processes.
11. helpers.c and helpers.h -> Some basic functions for using at different places.
12. commands1.c, commands2.c and commands.h -> Imp. functions for different commands and all of their implementations.

New Features coming soon maybe.... (V?)