Simple Shell

This is a simple shell. It executes commands, including those with arguments. It follows the betty style guide It can be used with or without a full path name. It can be used to execute standard commands in the PATH such as ls and pwd.

Directions for Use

Compile with this command:

gcc -Wall -Werror -Wextra -pedantic *.c -o <shell name here>

Invoke shell by typing its path name

old_shell$ ./shell
$

Built-ins

• cd - change directory

$ cd /home
$ pwd
home

• exit - exit shell

$ exit 99
old_shell$ echo $?
99

• alias - create an alias

$ alias pwd=ls
$ pwd
hello_world.txt

• setenv - set an environmental variable

$ setenv HELLO world
$ echo $HELLO
world

• unsetenv - unset an env

$ unsetenv HELLO
$ echo $HELLO

$

• env - list all environmental variables

$ env
XDG_SESSION_ID=4
TERM=xterm-256color
...

Other Features:

• && and || logical operators

$ ls
hello_world.txt
$ asgdnja || ls
./shell: 1: asgdnja: not found
hello_world.txt

• semicolon separator

$ ls; pwd
hello_world.txt
/home

• limited variable expansion

$ echo ~
/home/vagrant

Blog Post

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