| version | 2.0.0 |
| name | Mortgage Calculator |
| description | Calculate mortgage payments with equal-principal and equal-interest comparisons. Use when comparing loans, calculating payments, evaluating prepayment. |
| author | BytesAgain |
| homepage | https://bytesagain.com |
| source | https://github.com/bytesagain/ai-skills |
Mortgage Calculator
Multi-purpose utility tool for managing structured data entries related to mortgage and financial calculations. Add, list, search, remove, and export data items — all stored locally in a simple log-based format with full history tracking.
Commands
All commands are invoked via mortgage-calculator <command> [args].
| Command | Description |
|---|
run <args> | Execute the main function — logs and confirms execution of the specified operation |
config | Show the configuration file path ($DATA_DIR/config.json) |
status | Show current status (reports "ready" when the tool is operational) |
init | Initialize the data directory (creates the data folder if it doesn't exist) |
list | List all data entries from the data log file |
add <text> | Add a new dated entry to the data log (auto-prefixed with YYYY-MM-DD) |
remove <item> | Remove an entry and log the removal |
search <term> | Search the data log for a keyword (case-insensitive match via grep -i) |
export | Export all data from the data log to stdout |
info | Show current version number and data directory path |
help | Show the built-in help message with all available commands |
version | Print version string (mortgage-calculator v2.0.0) |
Data Storage
- Location:
~/.local/share/mortgage-calculator/ (override with MORTGAGE_CALCULATOR_DIR environment variable, or XDG_DATA_HOME)
- Data log:
data.log — stores all entries added via add, one per line, prefixed with YYYY-MM-DD
- History:
history.log — every command execution is recorded with a timestamp (MM-DD HH:MM command: details) for auditing
- Format: Plain text, one entry per line, human-readable
Requirements
- Bash 4+
- Standard Unix utilities (
date, grep, cat, echo)
- No external dependencies, no API keys, no network access needed
When to Use
- Financial record keeping — Use
mortgage-calculator add to log mortgage-related events (payments made, rate changes, lender communications) and build a local history
- Payment tracking — Record monthly payments, extra payments, or escrow changes with
add, then review the full log with list
- Comparison notes — Store notes from different loan scenarios or lender quotes using
add, then search to find specific terms or rates
- Data export for spreadsheets — Use
mortgage-calculator export to dump all entries to stdout and redirect to a file for import into Excel or Google Sheets
- Automation and scripting — Integrate
mortgage-calculator add and mortgage-calculator export into shell scripts or cron jobs for automated financial logging workflows
Examples
mortgage-calculator init
mortgage-calculator add "Monthly payment: ¥4,235.00 — principal ¥2,100 + interest ¥2,135"
mortgage-calculator add "Rate adjusted from 3.85% to 3.50% effective 2025-01-01"
mortgage-calculator add "Prepayment: ¥50,000 applied to principal, new balance ¥680,000"
mortgage-calculator list
mortgage-calculator search "rate"
mortgage-calculator search "prepayment"
mortgage-calculator export > mortgage-history.txt
mortgage-calculator status
mortgage-calculator info
mortgage-calculator run "quarterly review"
Output
All command output goes to stdout. Redirect to save:
mortgage-calculator list > all-records.txt
mortgage-calculator export > backup.txt
Configuration
Set the MORTGAGE_CALCULATOR_DIR environment variable to change the data directory:
export MORTGAGE_CALCULATOR_DIR="$HOME/my-mortgage-data"
mortgage-calculator init
Default location: ~/.local/share/mortgage-calculator/
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