luischaparroc / simple_shell Goto Github PK

• Handle the PATH

• Display a prompt and wait for the user to type a command. A command line always ends with a new line.

• The prompt is displayed again each time a command has been executed.

• The command lines are simple, no semicolons, no pipes, no redirections or any other advanced features.

• The command lines are made only of one word. No arguments will be passed to programs.

• If an executable cannot be found, print an error message and display the prompt again.

• Handle errors.

• You have to handle the “end of file” condition (Ctrl+D)

• handle arguments for the built-in exit

• Usage: exit status, where status is an integer used to exit the shell

• Write your own getline function

• Use a buffer to read many chars at once and call the least possible the read system call

• You will need to use static variables

• You are not allowed to use getline

Implement the builtin command cd:

• Changes the current directory of the process.

• Command syntax: cd [DIRECTORY]

• If no argument is given to cd the command must be interpreted like cd $HOME

• You have to handle the command cd -

• You have to update the environment variable PWD when you change directory

Implement the help built-in
Usage: help [BUILTIN]

Handle comments (#)

• Implement the alias builtin command

• Usage: alias [name[='value'] ...]

• alias: Prints a list of all aliases, one per line, in the form name='value'

• alias name [name2 ...]: Prints the aliases name, name2, etc 1 per line, in the form name='value'

• alias name='value' [...]: Defines an alias for each name whose value is given. If name is already an

• alias, replaces its value with value

• Implement the help built-in

• Usage: help [BUILTIN]

• Handle Ctrl+C: your shell should not quit when the user inputs ^C

• Handle variables replacement

• Handle the $? variable

• Handle the $$ variable

• Write a readme

• Write a man of the shell

• Authors should be added to the repository

• Implement the env built-in, that prints the current environment

• You are not allowed to use strtok

• Handle the && and || shell logical operators

• Usage: simple_shell [filename]

• Your shell can take a file as a command line argument

• The file contains all the commands that your shell should run before exiting

• The file should contain one command per line

• In this mode, the shell should not print a prompt and should not read from stdin

• Handle command lines with arguments

• Handle the commands separator ;

• Implement the exit built-in, that exits the shell

• Usage: exit

• You don’t have to handle any argument to the built-in exit

Implement the setenv and unsetenv builtin commands

setenv

• Initialize a new environment variable, or modify an existing one

• Command syntax: setenv VARIABLE VALUE

• Should print something on stderr on failure

unsetenv

• Remove an environment variable

• Command syntax: unsetenv VARIABLE

• Should print something on stderr on failure

• Implement the history built-in, without any argument

• The history built-in displays the history list, one command by line, preceded with line numbers (starting at 0)

• On exit, write the entire history, without line numbers, to a file named .simple_shell_history in the directory $HOME

• When the shell starts, read the file .simple_shell_history in the directory $HOME if it exists, and set the first line number to the total number of lines in the file modulo 4096

• Handle comments (#)