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7.8 KiB
7.8 KiB
TermTCP - Command Line TCP Terminal Client
A lightweight, zero-dependency command-line TCP client for connecting to TCP servers and BBS systems.
Features
- ✅ Minimal Dependencies - No GUI libraries, just standard C POSIX
- ✅ Multiple Host Support - Store and quickly connect to configured hosts
- ✅ Session Logging - Automatic timestamped logging of all traffic
- ✅ Color Output - Optional ANSI color for better readability
- ✅ Non-blocking I/O - Responsive input/output handling
- ✅ Command System - Built-in commands for connection management
- ✅ Configuration File - Easy setup via ~/.termtcprc
- ✅ Lightweight - Single C file, ~400 lines
Quick Start
Build
make -f Makefile_CLI
./termtcp
First Run
The application will create ~/.termtcprc with default configuration.
Connect
> connect 0 # Connect to first configured host
> list # Show all configured hosts
> status # Show connection status
Send Data
> Type anything here (not starting with /) to send to server
> Hello, BBS! # Sends "Hello, BBS!\r"
Disconnect
> disconnect # Close connection
> quit # Exit the application
Configuration
Edit ~/.termtcprc to add hosts:
# Format: host port name
# Comments start with #
localhost 8011 Local BBS
example.com 8011 Remote BBS
bbs.example.net 9000 Another System
Commands
Connection Commands
connect [N] - Connect to host N (default: 0)
disconnect - Close current connection
status - Show connection status
list - List all configured hosts
Session Commands
log on - Enable session logging
log off - Disable logging
color on - Enable colored output
color off - Disable colored output
Help & Exit
help - Show command list
quit - Disconnect and exit
exit - Same as quit
Command-Line Options
termtcp [OPTIONS]
Options:
-c, --connect N Auto-connect to host N on startup
-l, --log Enable logging on startup
-n, --no-color Disable colored output
-h, --help Show help message
Examples
Connect and Log Automatically
termtcp -c 0 -l
# Connects to host 0 and starts logging
No Color Mode
termtcp -n
# Runs without ANSI colors
Standard Usage
termtcp
# Starts interactive, allows manual connection
Logging
When logging is enabled:
- Creates timestamped log files in current directory
- Format:
hostname_port_YYYYMMDD_HHMMSS.log - Records both sent and received data with timestamps
- Automatic log opening when connecting
- Use
log offto disable
Example log entry:
[14:35:22] SEND: Hello, World
[14:35:23] RECV: Welcome to the system!
Building
Dependencies
- GCC or Clang
- POSIX-compliant system (Linux, macOS, BSD)
- Standard C library
Compilation
# Standard build
gcc -Wall -O2 -o termtcp termtcp_cli.c
# Or use Makefile
make -f Makefile_CLI
Make Targets
make -f Makefile_CLI build # Build
make -f Makefile_CLI run # Build and run
make -f Makefile_CLI debug # Debug build
make -f Makefile_CLI install # Install to /usr/local/bin/
make -f Makefile_CLI clean # Remove artifacts
Usage Patterns
Simple Connection
$ termtcp
> list
Configured Hosts:
[0] localhost:8011 - Local BBS
[1] example.com:8011 - Remote BBS
> connect 0
Connecting to localhost:8011...
Connected to: Local BBS
[Status] Connected to localhost:8011
> help
Available Commands:
connect [host#] - Connect to a host (default: 0)
...
> Hello there!
Scripted/Automated Connection
# Auto-connect and log
termtcp -c 0 -l
# Non-interactive, pipe commands
echo -e "connect 0\nQUERY\nquit" | termtcp
Session Logging for Support
> log on
> [do something that fails]
> log off
# Now you have a complete log to send to support
Configuration File Format
The ~/.termtcprc file is simple text format:
# Comments start with #
# Empty lines are ignored
# Format: hostname port shortname
# BBS Systems
bbs1.example.com 9000 BBS One
bbs2.example.com 9000 BBS Two
# Local Services
localhost 3000 Local Dev
192.168.1.10 8080 Lab Server
# Remote Services
production.example.com 443 Production
Notes:
- Hostname: Can be IP or FQDN
- Port: Numeric port number (1-65535)
- Shortname: Display name, no spaces
Troubleshooting
"Connection timeout"
- Check hostname/IP is correct
- Check port number is correct
- Verify the server is running
- Check firewall settings
"Connection refused"
- Server is not listening on that port
- Check port number
- Server may be down
"Failed to resolve hostname"
- Check DNS configuration
- Try using IP address instead
- Check hostname spelling
Terminal appears frozen
- Press Ctrl+C to interrupt
- Type
quitand Enter to exit gracefully
Characters not displaying
- Try
color offif color codes appear - Check terminal encoding (should be UTF-8)
Performance
- Memory Usage: ~50KB
- CPU Usage: Minimal (event-driven)
- Binary Size: ~40KB (stripped)
- Startup Time: <100ms
- Max Line Length: 512 bytes
Technical Details
Implementation
- Single-threaded event loop using
select() - Non-blocking socket I/O
- Raw terminal mode for responsive input
- Efficient circular buffering for display
Compatibility
- Linux: Full support
- macOS: Full support
- BSD: Full support
- Windows: Possible with Cygwin/WSL
Signal Handling
- SIGTERM: Graceful shutdown
- SIGINT (Ctrl+C): Immediate exit
Limitations
- Maximum line length: 512 characters
- Maximum hosts in config: 5
- Single connection at a time
- No TLS/SSL support (use tools like
openssl s_clientfor secure connections) - No proxy support (use SSH tunneling instead)
Future Enhancements
- IPv6 support
- Scripting/automation interface
- Terminal scrollback buffer
- Search in history
- Aliases for commands
- Custom prompt configuration
- Binary mode (for file transfer)
Comparison: CLI vs GTK3 Version
| Feature | CLI | GTK3 |
|---|---|---|
| Dependencies | None | GTK3 dev files |
| Binary Size | 40KB | 500KB+ |
| Memory | 50KB | 20MB+ |
| Startup | <100ms | 500ms+ |
| GUI | No | Yes |
| Multiple Connections | No | Yes (planned) |
| Port Monitoring | No | Yes |
| Scripting | Yes | No |
| Configuration | .termtcprc | GUI + ini file |
Installation
From Source
git clone <repo>
cd termtcp
make -f Makefile_CLI install
termtcp
Pre-built (if available)
sudo apt install termtcp # Ubuntu/Debian
sudo dnf install termtcp # Fedora
Creating a Desktop Entry
On Linux, create ~/.local/share/applications/termtcp.desktop:
[Desktop Entry]
Type=Application
Name=TermTCP
Exec=gnome-terminal -- termtcp
Terminal=true
Categories=Utility;Network;
Examples & Use Cases
Connect to a BBS
# Edit ~/.termtcprc with BBS addresses
termtcp
> connect 0
> help
System Monitoring
# Check system metrics from a remote server
termtcp -c 0
> STATUS
> QUERY
Testing TCP Services
# Quick test of a TCP service
termtcp -c 0
> HELLO
> [see response]
> quit
Log Everything for Debugging
termtcp -l
> connect 0
> [do something]
> log on
> [reproduce issue]
> log off
Getting Help
- Type
helpin the application - Check ~/.termtcprc for configuration examples
- Review this README
- Check application output for error messages
License
Same as TermTCP project.
Version History
- v1.0.0 (2026-06-23) - Initial CLI release
- Basic TCP connectivity
- Command system
- Session logging
- Configuration file support
TermTCP CLI - Lightweight TCP terminal client for power users.
Start with: make -f Makefile_CLI && ./termtcp