ShSh - Shitty Shell

A shitty command-line shell written in C with remote command execution support.

Features

• Interactive mode (REPL) and script execution
• Command pipes
• Background process execution
• Input/output redirection
• TCP server for remote command execution
• Built-in commands: cd, exit, jobs

Syntax

# Comments
;           # Command separator
|           # Pipe
&           # Background execution
>           # Redirect stdout to file
<           # Redirect stdin from file
'...'       # Escape special characters
>@ host:port # TCP output redirection (not implemented)
<@ host:port # TCP input redirection (not implemented)

Grammar

<program> ::= <command> ( ";" )? | <command> ";" <program>

<command> ::= <bg_command> | <piped_command> | <command_body>

<piped_command> ::= <command_body> "|" <command>
<bg_command> ::= <command_body> "&"

<command_body> ::= <command_word> <arguments> <io_redirection>?

<arguments> ::= ( " " <argument> )*
<argument> ::= <unescaped_word> | <escaped_word>

<io_redirection> ::= <file_io> | <tcp_io>
<file_io> ::= ">" <filename> | "<" <filename>
<tcp_io> ::= ">@" <ip>:<port> | "<@" <ip>:<port>

<escaped_word> ::= "'" <any_chars> "'"
<unescaped_word> ::= <non_special_chars>+

Usage

Local mode

# Interactive mode
./shsh

# Execute script
./shsh script.sh

Server mode

# Start server
./shsh -s -p 8080

# Connect client
nc 127.0.0.1 8080

Command examples

# Simple commands
echo "Hello World"
ls -la

# Pipes
ls -la | grep txt

# Background execution
sleep 10 &

# Redirection
echo "test" > output.txt
cat < input.txt

# Command sequences
cd /tmp; pwd; ls

Build

make            # Debug build
make RELEASE=1  # Release build
make clean      # Clean

Limitations

• TCP redirection (>@, <@) is declared in grammar but not implemented
• Command substitution (``) is not supported
• Wildcard expansion (*) doesn't work
• Escape characters (\) work partially

Author

Illia Chaban ic-it@mail.com