Fetch variables values from yml and pass to shell script?

Question

data.yml

variables:
  count: "100"
  name: "sss"
  pass: "123"

file.sh

#!/bin/bash
echo "Details are "$name":"$pass" - Total value "$count"

I need to fetch the variable values from data.yml and pass to file.sh

calling file.sh should give Output:

Details are sss:123 - Total value 100

Why is this tagged as _bash_ **and** _powershell_? – user1934428 Mar 08 '22 at 10:52 — user1934428, Mar 08 '22 at 10:52
@phd i have updated the tags remove the downvote. Thanks – rowoc Mar 08 '22 at 14:04 — rowoc, Mar 08 '22 at 14:04

Cole Tierney · Accepted Answer · 2022-11-05T14:06:30.550

3

Read name value pairs from yq and use bash printf -v to initialize variables. A little over the top, but a nice way to initialize a script. Note that adding variables does not change the while loop.

file.sh

#!/bin/bash

while read -r key val; do
    printf -v "$key" "$val"
done < <(yq '.variables[] | key + " " + .' data.yml)

echo "Details are $name: $pass - Total value $count"
echo 'Some extra variables:'
echo "\$address: $address, \$phone: $phone, \$url: $url"

data.yml

variables:
  count: "100"
  name: "sss"
  pass: "123"
  address: "42 Terrapin Station"
  phone: "999-999-9999"
  url: "http://www.example.com"

output

Details are sss: 123 - Total value 100
Some extra variables:
$address: 42 Terrapin Station, $phone: 999-999-9999, $url: http://www.example.com

edited Nov 05 '22 at 14:06

answered Mar 09 '22 at 00:17

Cole Tierney

9,571
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it gives me "Error: bad expression, please check expression syntax" for the yq command – sanurah Nov 05 '22 at 10:57
Can you post an example somewhere? – Cole Tierney Nov 05 '22 at 12:20
https://github.com/sanurah/yamlexample I used the same code. Could it be something in my local environment? may be bash version – sanurah Nov 05 '22 at 12:27
What version of yq are you using? – Cole Tierney Nov 05 '22 at 12:39
yq version is 4.29.2 – sanurah Nov 05 '22 at 12:42
I'm using yq 3.1.0. I'll try upgrading and see if I can I can reproduce the error. – Cole Tierney Nov 05 '22 at 12:45
1

I've upgraded to yq 4.29.2 and now I'm seeing `Error: bad expression, please check expression syntax`. I'll need to change the yq expression for version 4 and above. – Cole Tierney Nov 05 '22 at 12:54
1

Thanks. I tried to play around with it but could not fix. If you find a solution please update the answer for new versions. – sanurah Nov 05 '22 at 12:57
1

Added support for yq 4 and above. The yq command is a lot cleaner now. Thanks for your report! Please let me know if this works for you. – Cole Tierney Nov 05 '22 at 14:10
1

nice. that worked – sanurah Nov 05 '22 at 15:15

gindex · Answer 2 · 2022-03-08T19:34:33.650

2

There is a cli tool yq to parse yaml files.

The script would look like this:

#!/usr/bin/env bash
name=$(yq '.variables.name' data.yaml)
pass=$(yq '.variables.pass' data.yaml)
count=$(yq '.variables.count' data.yaml)

echo "Details are $name: $pass - Total value $count"

Of course you can also pass the file as argument.

edited Mar 08 '22 at 19:34

answered Mar 08 '22 at 10:40

gindex

285
1
11

is there any other solution without using any other tool/cli @gindex – rowoc Mar 08 '22 at 11:28
@rowoc YAML is complex so there's no general solution other than using a specialised tool for parsing it; that said, if your input is as simple as what you're showing in the question then you can do the job with other (basic/standard) tools – Fravadona Mar 08 '22 at 12:41
Yes, there are more options how to parse yaml on [command line](https://stackoverflow.com/questions/5014632/how-can-i-parse-a-yaml-file-from-a-linux-shell-script), but yq is most simple one. yq is widely adopted also. Why you cannot use it? – gindex Mar 08 '22 at 12:42
@gindex can you recheck your solution , I tried that not working – rowoc Mar 08 '22 at 12:44
Should work now. Please check the name of the local file and in the script . – gindex Mar 08 '22 at 12:47
Thanks its working, can the code be minimize, I am having more varaibles, for each i have to again write yq '.variables.xxxx' data.yml . Any minification can be done @gindex – rowoc Mar 08 '22 at 12:59
I have tried this also but its only taking last 3 variable, if i have more data,its takes last 3 only. . <(sed -nr '/variables:/,$ s/ ([A-Z_]+): (.*)/\1=\2/ p' .data.yml) – rowoc Mar 08 '22 at 13:01
@rowoc If you need a solution that will scale smoothly, you might be interested in [this answer](https://stackoverflow.com/questions/71393380/fetch-variables-values-from-yml-and-pass-to-shell-script/71402938#71402938 "support an arbitrary number of variables"). – Cole Tierney Mar 09 '22 at 18:28

score 1 · Answer 3 · answered Mar 08 '22 at 15:52

1

You can use a single call to yq and put values in an array :

#!/usr/bin/env bash
  
mapfile -t array < <(yq '.variables[]' data.yml)
declare -p array

answered Mar 08 '22 at 15:52

Philippe

20,025
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32

Fetch variables values from yml and pass to shell script?

3 Answers3

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