flywithu/Learning-Bitcoin-from-the-Command-Line
1
1
Fork 0
mirror of https://github.com/ChristopherA/Learning-Bitcoin-from-the-Command-Line.git synced 2025-06-07 16:06:26 +00:00
Code Issues Releases Wiki Activity

Merge pull request #250 from csralvall/master

Browse Source 
Fix indexing typos
This commit is contained in:
Shannon Appelcline 2021-06-30 14:30:21 -10:00 committed by GitHub
commit e2543d64b3
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 2 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
04_2__Interlude_Using_JQ.md
View File

@ -51,7 +51,7 @@ $ bitcoin-cli sendrawtransaction $signedtx
Grabbing data out of a JSON object is easy, but what if that JSON object is in a JSON array? The `listunspent` command offers a great example, because it'll usually contain a number of different transactions. What if you want to capture specific information from _one_ of them? Grabbing data out of a JSON object is easy, but what if that JSON object is in a JSON array? The `listunspent` command offers a great example, because it'll usually contain a number of different transactions. What if you want to capture specific information from _one_ of them?
When working with a JSON array, the first thing you need to do is tell JQ which index to access. For example, you might have looked through your transactions in `listunspent` and decided that you wanted to work with the second of them. You use `'.[1]'` to access that first element. The `[]` says that we're referencing a JSON array and the `0` says we want the 0th index. When working with a JSON array, the first thing you need to do is tell JQ which index to access. For example, you might have looked through your transactions in `listunspent` and decided that you wanted to work with the second of them. You use `'.[1]'` to access that second element. The `[]` says that we're referencing a JSON array and the `1` says we want the 1st index.
``` ```
$ bitcoin-cli listunspent | jq -r '.[1]' $ bitcoin-cli listunspent | jq -r '.[1]'
{ {
@ -68,7 +68,7 @@ $ bitcoin-cli listunspent | jq -r '.[1]'
"safe": true "safe": true
} }
``` ```
You can then capture an individual value from that selected array by (1) using a pipe _within_ the JQ arguments; and then (2) requesting the specific value afterward, as in the previous example. The following would capture the `txid` from the 0th JSON object in the JSON array produced by `listunspent`: You can then capture an individual value from that selected array by (1) using a pipe _within_ the JQ arguments; and then (2) requesting the specific value afterward, as in the previous example. The following would capture the `txid` from the 1st JSON object in the JSON array produced by `listunspent`:
``` ```
$ bitcoin-cli listunspent | jq -r '.[1] | .txid' $ bitcoin-cli listunspent | jq -r '.[1] | .txid'
91261eafae15ea53dedbea7c1db748c52bbc04a85859ffd0d839bda1421fda4c 91261eafae15ea53dedbea7c1db748c52bbc04a85859ffd0d839bda1421fda4c