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0x16. C - Simple Shell

0. Betty would be proud Write a beautiful code that passes the Betty checks

Simple shell 0.1 Write a UNIX command line interpreter.

2. Simple shell 0.2 Simple shell 0.1 + Handle command lines with arguments

3. Simple shell 0.3 Simple shell 0.2 + Handle the PATH fork must not be called if the command doesn’t exist

4. Simple shell 0.4 Simple shell 0.3 + Implement the exit built-in, that exits the shell Usage: exit You don’t have to handle any argument to the built-in exit

5. Simple shell 1.0 Simple shell 0.4 + Implement the env built-in, that prints the current environment

6. Simple shell 0.1.1 Simple shell 0.1 + 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 You don’t have to: be able to move the cursor

7. Simple shell 0.2.1 Simple shell 0.2 + You are not allowed to use strtok

Simple shell 0.4.1 Simple shell 0.4 + handle arguments for the built-in exit Usage: exit status, where status is an integer used to exit the shell

9. setenv, unsv Simple shell 1.0 + 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

10. cd Simple shell 1.0 + 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

11. ; Simple shell 1.0 + Handle the commands separator ;

12. && and Simple shell 1.0 + Handle the && and || shell logical operators

13. alias Simple shell 1.0 + 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

14. Variables Simple shell 1.0 + Handle variables replacement Handle the $? variable Handle the $$ variable

15. Comments Simple shell 1.0 + Handle comments (#)

16. File as input Simple shell 1.0 + 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