price-list-update

---
name: price-list-update
description: Finds every place a price appears in your documents, spreadsheets and website files, shows the full list before changing anything, then applies the change and logs every edit so it can be reversed.
---

# Push one price change through every file that mentions it

In: one folder, the old price and the new one. Out: a list of every place that price appears for you to read first, then the change applied only where you said, a log of every edit, and a one-command undo.

Run it from the folder above the files:

```
codex exec -C "the folder" - < the-prompt.md
```

## What it does

1. **Take one folder and refuse to step outside it:** resolve the folder the owner names to an absolute path and store it. Refuse to run on a drive root, on the Windows or Program Files folders, or on the whole user profile, because a price sweep at that level reaches application settings and other people's documents. Do not follow a shortcut or a symbolic link that leads out of the folder. Skip any `.git` and `node_modules` folder. Before every single write, resolve the target path again and confirm it still begins with the stored folder path, because a path is only safe after it has been resolved, not when it was first read.

2. **Copy the whole folder before opening any file for writing:** make `price-backup-YYYY-MM-DD-HHMM` alongside it and copy everything in. This is the floor under the job, not the record of it: step 8 still logs every individual edit, because restoring a whole folder to undo one wrong line loses every other change made that day.

3. **Get the old price, the new price and the date it applies from, in writing:** the exact old figure, the exact new figure, the product or service it belongs to, and the date the new price takes effect. Never accept "put everything up 10 percent" as one instruction: work out each individual figure, list them, and have them confirmed one by one, because a percentage applied by a machine to 40 numbers is 40 chances to be wrong in a way nobody can check by reading.

4. **Search for every written form of the number, and match on whole words:** one price appears as 95, 95.00, £95, 95 GBP, and often spelled out. If the business quotes both with and without VAT, the same price also appears as its VAT-inclusive twin, 114.00 at the current 20 percent standard rate, so treat that as a second search rather than hoping to catch it. Match on word boundaries, which is what ripgrep's `-w/--word-regexp` does: "Require that all matches of the pattern be surrounded by word boundaries". Without it, searching for 95 also hits 195, 1995 and the postcode. Search the literal figure with `-F/--fixed-strings`, which "disable[s] regular expression matching and treat[s] the pattern as a literal string", so the full stop in 95.00 does not quietly match any character.

5. **Open the file types that hide their text:** the standard search tools skip, by their own documentation, files matching `.gitignore`, hidden files and directories, and binary files. Price lists live in exactly those places. So unzip and read `.docx` and `.xlsx`, which are compressed XML inside; extract text from PDFs; read `.csv` and `.txt`; check hidden folders explicitly; and list image and PDF filenames separately as things a person must check by eye, because a price baked into a picture of a menu cannot be edited by this job at all. Report the count of hits per file type so the owner can see what was searched, not just what was found.

6. **Sort every hit into three buckets before proposing a single change:** CHANGE, for a live price, a website page, the current price list, a quote template, a rate card. FROZEN, for anything already issued: an invoice, a receipt, a signed order, a past accounts file. UNSURE, for anything the run cannot place, and for any hit that is a number matching by coincidence, an order reference, a house number, a phone number, a date. FROZEN files are never edited, ever: HMRC requires VAT records to be kept for at least 6 years and requires a business to "keep copies of all the sales invoices you issue even if you cancel them or produce one by mistake". A wrong figure on an issued invoice is corrected by issuing a new document, not by editing the old one.

7. **Dry run, printed as a list a person can actually read, then stop:** one line per hit, showing the file, the line number, the whole line as it reads now, the whole line as it would read, and the bucket. Group by folder, and print the totals per bucket at the top. Change nothing. The owner reads the list and says which lines go ahead. A dry run is not permission, and silence is not permission either.

8. **Apply only the approved lines, one at a time, as exact literal replacements:** replace the exact matched text at that exact line number, never by re-running a pattern across the whole file, because the file may have changed since the plan was written. After each file, append to `price-change-log.csv`: the file path, the line number, the old text, the new text, a timestamp, and the file's size and modification time before and after. Write the log as you go rather than at the end, so a run that stops halfway still leaves a complete record of what it had already done.

9. **Write the undo, and prove it works before saying the job is done:** generate `undo-price-change` from the log, line by line, never from memory. Then test it: copy one changed file into a scratch folder, run the undo against the copy, and confirm it comes back byte for byte identical to the same file in the backup from step 2. Delete the scratch copy. Report the counts per bucket, the number of lines changed, where the backup lives, where the log lives, and the list of anything in UNSURE that still needs a person.

## Then it checks

1. Every path written begins with the resolved absolute path of the named folder. One that does not stops the run immediately, before anything else is reported.
2. The number of lines changed equals the number of lines the owner approved equals the number of rows in `price-change-log.csv`. Three numbers, one value, or the run stops.
3. No file in the FROZEN bucket has a modification time later than the start of the run. An issued invoice that changed is a failure, not a warning.
4. Search again for every written form of the old price. Every remaining hit sits in FROZEN or UNSURE and is named in the report. A remaining hit in a CHANGE file means the sweep missed a form of the number.
5. Search for the new price and confirm it appears at exactly the approved line numbers and nowhere else, so nothing was written twice.
6. Open three changed lines at random and read them whole: the currency symbol is present and not doubled, the decimal places are unchanged, the number is not stuck to the word beside it, and the sentence still reads correctly.

Any check fails: name it, redo that step once. Failed twice: say what is wrong and stop.

## Rules
- Public information only.
- Never invent a fact, a number or a quote.
- Nothing is edited until the dry run has been read and approved by the owner, line by line or bucket by bucket. Approving the plan is the only permission that counts.
- Never write to a file outside the named folder, and never follow a shortcut or symbolic link out of it. Resolve the path again immediately before every write.
- Never edit an issued invoice, receipt, credit note or past accounting record. VAT records must be kept for at least 6 years, and copies of sales invoices must be kept even when cancelled or produced by mistake. A wrong figure is corrected by a new document.
- A price shown to a consumer must be the final price including VAT and all other taxes, and must be "unambiguous, easily identifiable, clearly legible". A half-finished price change leaves two different prices live at once, which is a legal exposure and not merely untidy. Where the change follows a change in the VAT rate, a general notice may cover adjusted prices for 14 days from the date the change takes effect. This prepares the work for a person to check, and is not legal advice.

## Built from
- ripgrep, https://github.com/BurntSushi/ripgrep, 68,055 stars read from api.github.com on 7 September 2026: its GUIDE.md gives the exact behaviour behind step 4, that `-w/--word-regexp` will "Require that all matches of the pattern be surrounded by word boundaries" and that `-F/--fixed-strings` will "Disable regular expression matching and treat the pattern as a literal string". Its documented defaults, skipping `.gitignore` matches, hidden files and directories, and binary files, are the reason step 5 exists at all.
- sd, https://github.com/chmln/sd, 7,345 stars read from api.github.com on 7 September 2026: its `-p`/`--preview` flag, documented as "To preview changes: sd -p 'window.fetch' 'fetch' http.js". A preview flag shipped as a first-class feature of a replace tool is the argument for making the dry run in step 7 the default and the only route to a change.
- fastmod, https://github.com/facebookincubator/fastmod, 1,926 stars read from api.github.com on 7 September 2026: its review loop, where "you'll be shown a colored diff and asked if you want to accept the change ... reject it, or edit the line in question". Step 7 is that idea gathered into a single list a non-developer can read in one sitting, rather than a prompt per match.
- Keeping VAT records, HMRC, GOV.UK, https://www.gov.uk/charge-reclaim-record-vat/keeping-vat-records: "You must keep VAT records for at least 6 years", "keep copies of all the sales invoices you issue even if you cancel them or produce one by mistake", and that a wrong amount is put right by asking for a new invoice. That is the FROZEN bucket in step 6 and the rule that protects it.
- The Price Marking Order 2004, legislation.gov.uk, https://www.legislation.gov.uk/uksi/2004/102/body: article 1(2) defines the selling price as "the final price to be paid for a unit of a product, or a given quantity of a product, including VAT and all other taxes"; article 7(1)(a) requires price indications to be "unambiguous, easily identifiable, clearly legible"; article 11 allows a general notice "for a period of 14 days from the date any such change takes effect" after a change in the rate of VAT. That is the VAT-inclusive twin in step 4 and the 14 day figure in the rules.