mysh

A very unsafe, crude and simple shell implemented for educational purpose in coherence with INF1060. Some of the implementations were done in a manner to complete a course task, such as memory handling with datablocks and bitmap for the command-history.

Install

The shell is written in C and will compile with the help of a makefile. A 'obj' folder to place the .o files is required to compile. The makefile i located in the src folder.

mkdir obj

Normal mode:

Compile from the src folder:

make

Debug mode:

Prints various debug information.

make debug

Cleanup:

Removes .o files.

make clean

Supported commands:

• Builtins:
  • quit: Quits mysh
  • type: Returns command type
  • h: Print command/execution history.
  • h i: Run command i
  • h -d i: Delete history input i
  • jobs: List all running jobs
  • kill pid: Kill job
• Run programs in background using &.
  • Applications requiring TERM and DISPLAY variables set is NOT supported.
• Signal handling and exiting using 'Ctrl-d', 'Ctrl-z' etc.

Examples:

DEBUG printing.

vegarbov@mysh 0> pwd
DEBUG: Read: pwd

DEBUG: Read: hello github my old friend

DEBUG - BITMAP

00001111000000000000000000000000
00000000000000000000000000000000

DEBUG - DATABLOCKS

##hello gi##thub my ##old frie##nd      ##
##        ##        ##        ##        ##
##        ##        ##        ##        ##
##        ##        ##        ##        ##
##        ##        ##        ##        ##
##        ##        ##        ##        ##
##        ##        ##        ##        ##
##        ##        ##        ##        ##
##        ##        ##        ##        ##
##        ##        ##        ##        ##
##        ##        ##        ##        ##
##        ##        ##        ##        ##
##        ##        ##        ##        ##
##        ##        ##        ##        ##
##        ##        ##        ##        ##
##        ##        ##        ##        ##

DEBUG: Number of tokens saved to saveptr: 5
DEBUG: [0]: hello
DEBUG: [1]: github
DEBUG: [2]: my
DEBUG: [3]: old
DEBUG: [4]: friend
mysh: hello: command not found

Ctrl-d:

vegarbov@mysh 1>
CTRL-D caught, exiting mysh..

Commands:

vegarbov@mysh 0> xyz
mysh: xyz: command not found

&:

vegarbov@mysh 1> vim &
[1] 55929
vegarbov@mysh 2>

type:

vegarbov@mysh 2> type h
h is a shell builtin

h:

vegarbov@mysh 4> h
History list of the last 5 commands:
  5: h
  4: pwd
  3: cd
  2: ls
  1: h

Architecture

File	Description
mysh.c	Main shell functions
mysh.h	Header file for the entire project
bi.c	Built in functions
bm.c	Bitmap functions
mdll.c	Metadata linked list functions for history handling
makefile	make