One liner to replace the timestamp with current time in a file-CodePudding

I have a file which contains a timestamp:

"buildTimestamp": "2021-07-19T17:00:00Z"

I want to replace it with the current build time, using a one-line command.

date | xargs -I {} perl -pi -e 's/2021-07-19T17:00:00Z/"$0"/g' serviceProperties.json

But it's not working as expected. Any suggestions?

CodePudding user response：

You should really be using a JSON parser to handle JSON data. jq can do this job.

If your file looks like

{
  "foo": {
    "bar": {
      "buildTimestamp": "2021-07-19T17:00:00Z"
    }
  }
}

Then

jq '.foo.bar.buildTimestamp = (now | strftime("%FT%TZ"))' serviceProperties.json

outputs this on Feb 24, 2022 at 16:36:15 America/New_York

{
  "foo": {
    "bar": {
      "buildTimestamp": "2022-02-24T21:36:15Z"
    }
  }
}

CodePudding user response：

Assuming data in serviceProperties.json

[
    {
        "buildTimestamp": "2021-07-19T17:00:00Z"
    },
    {
        "buildTimestamp": "2021-07-19T17:00:00Z"
    },
    {
        "buildTimestamp": "2021-07-19T17:00:00Z"
    },
    {
        "buildTimestamp": "2021-07-19T17:00:00Z"
    }
]

After running date %FT%TZ | xargs -I % perl -pi -e 's/2021-07-19T17:00:00Z/%/g' serviceProperties.json

serviceProperties.json will be

[
    {
        "buildTimestamp": "2022-02-25T03:30:20Z"
    },
    {
        "buildTimestamp": "2022-02-25T03:30:20Z"
    },
    {
        "buildTimestamp": "2022-02-25T03:30:20Z"
    },
    {
        "buildTimestamp": "2022-02-25T03:30:20Z"
    }
]

As you are replacing with $0 it will take arguments from perl command and hence you will have unexpected results. Instead replacing with a helper using xargs will do the trick.

To learn more about how xargs is working in this case read here

CodePudding user response：

perl -pi -e 's/2021-07-19T17:00:00Z/'"$(date)"'/g' serviceProperties.json