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If you ever need to fight against this annoying json trend (e.g., when your tool only emits certain information in stupid ungrepable json), consider filtering t

If you ever need to fight against this annoying json trend (e.g., when your tool only emits certain information in stupid ungrepable json), consider filtering the output through a gron so that it becomes saner.

dylan604 5y ago
why is JSON ungrepable? grep key file.json | awk -F: '{print $2}' if you're already searching for a key, seems like you're just wanting the value. granted, i hardly ever (have i actually ever??) interact with JSON this way, so i'm not exactly familiar with pitfalls.
- b3morales 5y ago
  When it's not formatted, just emitted as a single line. (Granted grep still works, but...not nicely.)
  - dylan604 5y ago
    gotcha. i'm imagining a pretty gnarly regex to return the data after the first colon after the match but only up until the next comma or square bracket or curly bracket. yeah, that's unpleasant. thankfully, there are tools like jq to help maintain one's sanity
    - akyoan 5y ago
      To be honest I find it funny that anyone would attempt to “parse” such a simple format with the wrong tool when there are plenty that can extract data in dot notation.
- fragmede 5y ago
  The pitfall is that JSON has zero guarantees for how often line breaks do and don't occur, and is often used to represent hierarchical data. Grepping for 'key: foo', and some liberal use of -A and -B may find you what you're looking for, but grep is simply the wrong tool for that job. (And how do you handle a key with newlines in it?) jq [0] is the right tool, but jq's syntax is it's own, and is harder to use (unless you use it regularly). [0] https://stedolan.github.io/jq/ https://stedolan.github.io/jq/
  - dylan604 5y ago
    when all you have is a hammer, everything looks like a nail. i can see rudimentary attempts at trying to get some data on a system you might not have full control over and are just needing something. i'm sure we've all been logged into a remote system maintained by someone else. cavemen throwing rocks at the spaceship type scenarios.
- nrclark 5y ago
  JSON is greppable if all you need a simple key-value from a known format and indentation. It's much harder if you don't know the indentation/line breaks, or if it's whitespace-free, or if your key can ever appear in your data.
- throwawayboise 5y ago
  Or just: awk -F: '/key/ {print $2}' file.json
redact207 5y ago
Jq makes life easier. I'd say for complex output, using filters is more readable than using awk to extract random positions of substrings
trulyme 5y ago
Thank you, sounds very useful for quick queries: https://github.com/TomNomNom/gron https://github.com/TomNomNom/gron
hencoappel 5y ago
Grep is for simple text, jq allows much more powerful searching/selection. Don't get me wrong, I believe it should be a choice and not force JSON on users, but for some it's useful.

dylan604 5y ago

why is JSON ungrepable? grep key file.json | awk -F: '{print $2}' if you're already searching for a key, seems like you're just wanting the value. granted, i hardly ever (have i actually ever??) interact with JSON this way, so i'm not exactly familiar with pitfalls.

b3morales 5y ago
When it's not formatted, just emitted as a single line. (Granted grep still works, but...not nicely.)
- dylan604 5y ago
  gotcha. i'm imagining a pretty gnarly regex to return the data after the first colon after the match but only up until the next comma or square bracket or curly bracket. yeah, that's unpleasant. thankfully, there are tools like jq to help maintain one's sanity
  - akyoan 5y ago
    To be honest I find it funny that anyone would attempt to “parse” such a simple format with the wrong tool when there are plenty that can extract data in dot notation.
fragmede 5y ago
The pitfall is that JSON has zero guarantees for how often line breaks do and don't occur, and is often used to represent hierarchical data. Grepping for 'key: foo', and some liberal use of -A and -B may find you what you're looking for, but grep is simply the wrong tool for that job. (And how do you handle a key with newlines in it?) jq [0] is the right tool, but jq's syntax is it's own, and is harder to use (unless you use it regularly). [0] https://stedolan.github.io/jq/ https://stedolan.github.io/jq/
- dylan604 5y ago
  when all you have is a hammer, everything looks like a nail. i can see rudimentary attempts at trying to get some data on a system you might not have full control over and are just needing something. i'm sure we've all been logged into a remote system maintained by someone else. cavemen throwing rocks at the spaceship type scenarios.
nrclark 5y ago
JSON is greppable if all you need a simple key-value from a known format and indentation. It's much harder if you don't know the indentation/line breaks, or if it's whitespace-free, or if your key can ever appear in your data.
throwawayboise 5y ago
Or just: awk -F: '/key/ {print $2}' file.json

redact207 5y ago

Jq makes life easier. I'd say for complex output, using filters is more readable than using awk to extract random positions of substrings

trulyme 5y ago

Thank you, sounds very useful for quick queries: https://github.com/TomNomNom/gron https://github.com/TomNomNom/gron

hencoappel 5y ago

Grep is for simple text, jq allows much more powerful searching/selection. Don't get me wrong, I believe it should be a choice and not force JSON on users, but for some it's useful.