All tools › Read, not run
Explain a pattern
A pattern taken apart and said in words, or built from named pieces.
It runs entirely in this browser tab: the code you paste is never uploaded, and nothing here is executed, built or fetched — it is read and something else is written. Open your browser's network panel and try it.
Settings
- Direction
- Choices: Explain, Build one.
- Pieces
- Choices: The start, Digits, Letters, A word, A space, Anything at all, The end.
- Name the parts
- Named groups are easier to read and are not in every flavour.
How to use it
- Paste your text into the box above, or open a file.
- Adjust the settings beside it until the result is what you wanted.
- Copy the result, or save it as a file. The result updates as you type.
Questions
- Is my code uploaded anywhere?
- No. The whole application is carried as WebAssembly and runs on your own device. That matters here as much as anywhere: a curl command pasted out of a terminal has a live token in it, a stack trace has your customers' identifiers in it, and a configuration file has a password in the middle of a connection address.
- Does anything here run what I paste?
- Never. The command explainer explains and does not execute; the Dockerfile reader reads and does not build; the request builder writes a command and does not send it. Each tool says so on its own result, and each says what that costs it — a linter that did not build the image cannot tell you the image builds.
- Will an escape survive a round trip?
- Yes, and there is a test that says so: every language's escaper has its unescaper beside it, and an awkward string with quotation marks, backslashes, tabs, a null and an emoji in it goes through both for every language on every run of the test suite.
- Why does it refuse a pattern instead of matching nothing?
- Because matching nothing looks like an answer. The glob matcher reads a stated subset — the stars, the question mark, character classes, brace lists and a leading negation — and a pattern using anything else comes back named rather than quietly matching none of your files.
Other tools for read, not run
Test a glob
Which paths a pattern covers, with the syntax it does not read refused by name.
Read an identifier
Version, variant and the instant it was made — or the plain statement that it has none.
Identifier collisions
Titles as address-safe identifiers, with the ones that become the same named and numbered.
Explain a command
A command line taken apart and explained, never run — with the destructive parts named.
Read a Dockerfile
The faults that cost size or safety, including the secret that stays in a layer for ever.
Run to compose
A run command as the service that would do the same, with the ports and volumes kept.
Read a YAML file
The four things that break a YAML file, including the country code that reads as false.
All forty tools