[
    {
        "role": "user",
        "content": "I%27d%20like%20to%20sync%20my%20gmail%20to%20a%20linux%20host%20(debian%2013)%20using%20imap%20in%20the%20mh%20or%20nmh%20format.%20I%20understand%20I%20can%27t%20use%20isync%2Fmbsync%20to%20do%20this.%20what%20are%20some%20well%20respected%20alternatives%3F"
    },
    {
        "role": "assistant",
        "content": "If you want to sync Gmail over IMAP on Debian 13 *into* an MH/nmh-style folder layout (one file per message, directories for folders), there aren't many tools that do that *directly*. Most sync tools target Maildir or mbox. Here's what the landscape looks like, plus some reasonable workarounds.\n\n---\n\n## What \u201cMH / NMH format\u201d means\n\n- With MH (and its descendants nmh / mmh), each message is stored as its own file inside a folder, without the Maildir substructure (`new`, `cur`, `tmp`) Maildir uses. ([unix.stackexchange.com](https://unix.stackexchange.com/questions/439903/mh-format-is-special-different-from-both-mbox-and-maildir?utm_source=openai))  \n- This format is neither Maildir nor mbox; many tools work with Maildir or mbox, but MH is distinct. ([unix.stackexchange.com](https://unix.stackexchange.com/questions/439903/mh-format-is-special-different-from-both-mbox-and-maildir?utm_source=openai))\n\n---\n\n## Sync tools & their natural storage formats\n\nHere are some well-known IMAP sync or IMAP-backup tools, and what they *do* vs what they'd need in order to support MH / nmh.\n\n| Tool               | Native local store format(s)                                                | Can it do MH / nmh directly?                                | Comments |\n|--------------------|--------------------------------------------------------------------------------|-------------------------------------------------------------|----------|\n| **OfflineIMAP**    | Maildir                                                                               | No                                                         | It\u2019s often used to sync Gmail to local Maildir; doesn\u2019t support MH. ([en.wikipedia.org](https://en.wikipedia.org/wiki/OfflineIMAP?utm_source=openai)) |\n| **mbsync / isync** | Also Maildir (and some other local stores)                                | No                                                         | Same as above; works great for offline backups, but not with MH. ([seanh.cc](https://www.seanh.cc/2021/08/22/backup-fastmail-and-gmail-with-isync/?utm_source=openai)) |\n| **imapsync**       | IMAP \u2192 IMAP copying; not local file store                                   | No                                                         | Meant for copying mailboxes *between servers* or for backup; not for file-based MH layout. ([imapsync.lamiral.info](https://imapsync.lamiral.info/?utm_source=openai)) |\n| **Fetchmail**      | Pulls mail from IMAP/POP3, drops into local mail delivery (MDA / via procmail etc) | Possibly, via a custom delivery agent                       | You could use fetchmail + a custom procmail rule or script to write each message into an MH folder. Not \u201cbuilt-in\u201d support. |\n| **getmail**        | Various (Maildir, mbox, etc.)                                                 | Same as fetchmail: via custom post-processing              | More flexible in specifying destination formats; might be adaptable. |\n\n---\n\n## Well-respected alternatives that *can* be adapted (or partly satisfy)\n\nBecause direct MH exporters are rare, the best path is to use a tool that downloads/saves to Maildir or mbox, then convert or script the layout into MH. Here are approaches:\n\n1. **Fetchmail / getmail + custom deliver agent**\n\n   - Use fetchmail or getmail to retrieve Gmail IMAP messages, dropping into a directory structure (like Maildir or mbox) with scripts triggered per message.\n   - Write a small script / delivery agent that moves each message file into its own file in an MH folder tree (e.g. using `nmh rcvstore`), maybe filtering by folder label.\n   - Pros: Flexible; you can craft whatever folder / filename scheme you like. Cons: More manual setup.\n\n2. **Use Maildir then convert to MH**\n\n   - Sync Gmail into a Maildir via **mbsync** or **OfflineIMAP**.\n   - Use conversion tools like `mbox2mh` (if converting from mbox) or scripts to read messages in Maildir and \u201cimport\u201d or move them into MH directories. For example, `mbox2mh` can take an mbox or a directory of mboxes and convert to MH layout. ([vale.thus.ch](https://vale.thus.ch/software/mbox2mh.html?utm_source=openai))\n   - Or write small Ruby / Python scripts to read Maildir and write into MH. (Maildir \u2192 MH conversion is conceptually fairly simple: each file in `new`/`cur` becomes a message file in MH, folder correspondence preserved.)\n\n3. **Direct \u201crcvstore\u201d from nmh**\n\n   - nmh includes commands like `rcvstore` which deliver mail into MH folders. If you can feed the message (raw RFC-822) to that command, you can build a pipeline: fetch IMAP, generate raw message files, then `rcvstore` them.\n   - This approach might work when combined with scripts or simple programs that connect via IMAP, fetch messages, dump them, and pass them to `rcvstore`.\n\n---\n\n## What you\u2019ll likely need to build\n\nBecause there\u2019s no mature, widely used tool that *directly* keeps an active IMAP sync into an MH-compatible layout (as far as I\u2019ve found), here\u2019s a suggested architecture (on Debian 13) that balances usability and maintainability:\n\n- **IMAP fetch**: Use `getmail6` or `fetchmail` to pull new mail. These tools can support modern Gmail authentication (app passwords / OAuth2 depending on Gmail\u2019s current policy).  \n- **Folder handling**: As Gmail \u201cfolders\u201d are really \u201clabels\u201d, map them in your fetch configuration (or post-processing) to MH folders.  \n- **Message delivery**: For each new message, write it as a file in the right MH folder \u2014 ideally via `rcvstore` or equivalent.  \n- **Deletion / flags**: If you need two-way sync (flag changes, deletes), you\u2019ll need additional logic \u2014 likely some polling of the IMAP \u201cseen\u201d, \u201cdeleted\u201d flags, then mapping them to MH actions (`rmm`, etc.). This gets involved.\n\n---\n\n## Summary: Your best options\n\n- For a comparatively simple read-only backup into MH style, use **fetchmail or getmail**, write the raw messages, then use `rcvstore` part of nmh to store them in MH folders.\n- For two-way sync or live usage, there isn't a packaged tool that directly keeps MH matching Gmail IMAP fully. You\u2019d need to build custom glue with IMAP client libraries + nmh commands.\n- If you're okay with Maildir initially, you can sync with mbsync / OfflineIMAP (simplest), then convert into MH periodically.\n\n---\n\nIf you want, I can sketch a sample setup script / config (on Debian 13) to do a working Gmail \u2192 MH sync using fetchmail + nmh, taking Gmail labels into folder names, etc. Do you want me to put that together?"
    },
    {
        "role": "user",
        "content": "can%20i%20convert%20an%20entire%20maildir%20directory%20to%20mh%20directory%20using%20a%20single%20command%3F"
    },
    {
        "role": "assistant",
        "content": "Short answer: There\u2019s no *single built-in command* that universally converts a Maildir to MH/NMH format. But you *can* use the `nmh inc` command to import Maildir-format mail into an MH-format folder, which is probably the closest thing. Plus a small script or one-liner can help convert all folders at once.\n\n---\n\n## \ud83d\udee0 Option 1: `nmh inc`\n\nThe `nmh inc` command (\u201cincorporate\u201d) is part of nmh, and it supports using a Maildir directory as the \u201cmail drop\u201d. Here\u2019s how it works:\n\n- If you run `inc +folder` with no special arguments, it will incorporate messages from your \u201cmaildrop\u201d (usually a file or directory) into an MH folder. If that maildrop is a directory, nmh treats it as Maildir format. ([mankier.com](https://www.mankier.com/1/inc?utm_source=openai))\n- It will move (or zero/truncate) the message drop unless you tell it not to. You also get options to add new messages to `unseen` sequences in MH folders. ([mankier.com](https://www.mankier.com/1/inc?utm_source=openai))\n\nExample:\n\n```bash\ninc +my-mh-folder\n```\n\nAssuming `~/Maildir` is your maildrop (configured in your nmh profile), this imports all Maildir messages into `+my-mh-folder` in MH format.\n\n---\n\n## \ud83d\udd01 Option 2: Convert entire Maildir tree via script + `rcvstore`\n\nIf you have many folders in Maildir and want them mirrored into MH layout, you can use a simple shell script that:\n\n- walks the Maildir folder structure  \n- for each folder, for each message file in `new/` + `cur/` subdirs  \n- pipes each message into `rcvstore +MHfoldername`\n\nHere\u2019s a sketch:\n\n```bash\n#!/bin/bash\nMAILDIR=~/Maildir\nMHROOT=~/Mail\n\n# Loop over Maildir folders\ncd \"$MAILDIR\"\nfind . -type d -mindepth 1 | while read -r fld; do\n  mhfld=\"${fld#./}\"                    # remove leading ./\n  mkdir -p \"$MHROOT/$mhfld\"\n  for mboxdir in \"$fld\"/new \"$fld\"/cur; do\n    [ -d \"$mboxdir\" ] || continue\n    for msg in \"$mboxdir\"/*; do\n      [ -f \"$msg\" ] || continue\n      rcvstore +$MHROOT/$mhfld < \"$msg\"\n    done\n  done\ndone\n```\n\nThis effectively processes every message and writes it into the proper MH folder. You can tweak it to preserve \u201cseen\u201d status via MH sequences, etc.\n\n---\n\n## \u2705 Conclusion\n\n- `nmh inc +folder` is your \u201csingle command\u201d solution for *one* Maildir drop \u2192 MH folder conversion.  \n- For converting *an entire Maildir tree*, a simple script + `rcvstore` is your best bet, and with a loop you can do it with one invocation of your script.\n\nIf you like, I can pull together a polished script that handles folders, unseen sequences, and cleans up after itself \u2014 ready to drop into Debian 13."
    }
]