Implementation of shell in c

K.Lakshmi Nirmala (2021101126)

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Requirements

• Bash Terminal
• Linux OS (Preferably ubuntu)

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Important Note

• The following commands are with respect to the write in vscode and execute it in vscode and i run it on ubuntu

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Commands to execute file

Open the file ../2021101126_Assignment-3 directory and then execute these commands

$ make
$ ./terminal

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Commands implemented in this shell

• ECHO : echo prints what we are given in the command line after echo command and this command written in echo.c
• CD: cd changes directory according to our input, prints sleep time if there is any sleep command given by us and implemented in cd.c
• PINFO:prints out process info according to the given pid and implemented in pinfo.c
• DISCOVER : Behaves like find command,supports -f -d flags and implemented in discover.c
• LS : prints list of files and folders, supports -l -a -al or -la flags and implemented in ls.c
• HISTORY : prints last 10 commands executed by terminal and also prints commands according to our given count ,saves in [history.txt] implemented in history.c
• JOBS: prints all the running and stopped process, supports -r -s flags and implemented in jobs.c
• SIG : sig command takes the signal number and job numbers and does operation on the job according to the signal number and implemented in sig.c
• FG : It takes background process to the foreground according to the given job number and implemented in fg.c
• BG : It resumes stopped process to running in the background according to the job number and implemented in bg.c
• EXIT : This shell exits on exit command or ctrl+d click

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Additional Featues

• This shell supports Autocompletion on tab press
• Supports system commands which were not implemented by me
• Supports input output redirection and piping
• Handles ctrl+c , ctrl+d and ctrl+z signals
• Handles multiple commands
• prints message after exiting background process
• prints special outputs in colored

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Example commads

• ls:

$ls
$ls -a
$ls -al
$ls -l
$ls -la

• echo:

$ echo hello world
# for inputoutputredirection
$ echo hello > out.txt
$ echo hello >> out.txt

• cd:

$ cd ..
$ cd folderpath/foldername
$ cd filepath/filename
$ cd -

• pwd

$ pwd

• pinfo

$ pinfo
$ pinfo pid

• jobs

$ jobs
$ jobs -s
$ jobs -r

• fg

$ fg jobnumber

• bg

$ bg jobnumber

• sig

$ sig jobnumber signalnumber

• discover

$ discover -d
$ discover -f
$ discover foldername/folderpath filename/filepath

• input-outputredirection and piping

$ echo hello > out.txt
$ cat sample2.txt | head -7 | tail -5
$ cat < out.txt

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List of files

• shell.c
• status.c
• system_commands.c
• get_input.c
• user_prompt.c
• cd.c
• ls.c
• echo.c
• pwd.c
• discover.c
• fg.c
• bg.c
• sig.c
• jobs.c
• pinfo.c
• color.c
• history.c
• signal_handling.c
• redirection.c
• list.c contains pid and helps in jobs,fg,bg,sig

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Thankyou...

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