diary

A simple one-line diary application for the command line.

Current version: 0.9.1

diary is a lightweight CLI tool written in Go for keeping short daily notes in JSONL format.
Each entry is assigned a serial ID, only one entry is stored per date, and existing entries can be updated or deleted easily.

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What's New in 0.9.1

• Added listing by year and month with -m YYYY-MM
• Added case-insensitive text search with -s
• Added interactive search mode with -i
• Added automatic backup on add, update, and delete
• Added manual backup with -b
• Added restore from backup with -R
• Added restore confirmation that requires typing diary

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Features

• Simple command-line interface
• Store diary entries in JSONL format
• One entry per date
• Automatic serial ID assignment
• Update an existing entry by writing to the same date
• List recent entries
• List entries for a specific month
• Search entries case-insensitively
• Interactive narrowing search
• Show entries in oldest-first or newest-first order
• Optionally display serial IDs
• Delete entries by serial ID
• Automatic backup on write
• Manual backup and restore
• TOML-based configuration

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Data Format

Entries are stored as JSON Lines (.jsonl), one record per line.

Example:

{"id":1,"date":"2026-03-25","text":"Went for a walk.","created_at":"2026-03-25T21:00:00+09:00","updated_at":"2026-03-25T21:00:00+09:00"}
{"id":2,"date":"2026-03-26","text":"A quiet day.","created_at":"2026-03-26T22:00:00+09:00","updated_at":"2026-03-26T22:15:00+09:00"}

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Installation

Requirements

• Go 1.21 or later

Build

go mod init diary
go get github.com/pelletier/go-toml/v2
go build -o diary .

On Windows:

go build -o diary.exe .

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Configuration

The application uses a TOML configuration file:

~/.config/diary/config.toml

Example:

data_file = "C:\\Users\\yourname\\diary\\diary.jsonl"
max_len = 200

Options

• data_file: path to the JSONL data file
• max_len: maximum number of characters allowed in one entry

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Usage

Show help

diary

Add an entry for today

diary -a "A quiet day."

Add or update an entry for a specific date

diary -a 2026-03-25 "Went for a walk."

List the most recent 7 entries in oldest-first order

diary -l

List the most recent 30 entries in oldest-first order

diary -l 30

List the most recent 30 entries in newest-first order

diary -r -l 30

List all entries for a specific year and month

diary -m 2026-03 -l

List entries for a specific year and month in newest-first order

diary -m 2026-03 -r -l

Search entries case-insensitively

diary -s "walk"

Search entries in a specific month

diary -m 2026-03 -s "walk"

Start interactive search mode

diary -i

Create a backup immediately

diary -b

Create a backup in a specific directory

diary -b backups

Restore from a backup file

diary -R C:\path\to\diary-backup-20260413-164441-000000000.jsonl

This command first creates a safety backup of the current data.

It then asks you to type diary before it restores.

List entries with serial IDs

diary -n -l 30

List entries with serial IDs in newest-first order

diary -r -n -l 30

Delete an entry by serial ID

diary -d 3

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Command Summary

Command	Description
diary	Show help
diary -l [n]	List recent entries in oldest-first order
diary -m YYYY-MM -l [n]	List entries for the specified year and month
diary -s "query"	Search entries case-insensitively
diary -m YYYY-MM -s "query"	Search entries in the specified month
diary -i	Start interactive search mode
diary -r -l [n]	List recent entries in newest-first order
diary -n -l [n]	List recent entries with serial IDs
diary -r -n -l [n]	List recent entries with serial IDs in newest-first order
diary -a "text"	Add or update today's entry
diary -a YYYY-MM-DD "text"	Add or update an entry for a specific date
diary -d ID	Delete an entry by serial ID
diary -b [path]	Create a backup immediately
diary -R backup.jsonl	Restore from a backup file

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Behavior

• Only one entry is stored per date.
• Adding a new entry for an existing date updates the previous one.
• Serial IDs are assigned only when a new entry is first created.
• Updating an existing entry keeps its original serial ID.
• Deletion is performed by serial ID.
• Text search is case-insensitive.
• -i starts a prompt-based narrowing search loop and exits on an empty line.
• Add, update, and delete automatically create a timestamped .jsonl backup.
• Automatic backups are stored in an OS-local directory.
• Windows: %LOCALAPPDATA%\diary\backups
• Linux: ~/.local/share/diary/backups
• macOS: ~/Library/Application Support/diary/backups
• -b creates an immediate backup in the same default location unless a path is given.
• -R restores from a backup file, first saves the current data as a safety backup, and requires typing diary to proceed.

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Project Goals

This project aims to be:

• small
• readable
• easy to build
• easy to back up
• easy to manage with Git

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License

This project is licensed under the MIT License. See the LICENSE file for details.