Read YAML file from Bash script

LICENSE

MIT License

Copyright (c) 2014 Piotr Kuczynski

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

parse_yaml.sh

#!/bin/sh
parse_yaml() {
   local prefix=$2
   local s='[[:space:]]*' w='[a-zA-Z0-9_]*' fs=$(echo @|tr @ '\034')
   sed -ne "s|^\($s\)\($w\)$s:$s\"\(.*\)\"$s\$|\1$fs\2$fs\3|p" \
        -e "s|^\($s\)\($w\)$s:$s\(.*\)$s\$|\1$fs\2$fs\3|p"  $1 |
   awk -F$fs '{
      indent = length($1)/2;
      vname[indent] = $2;
      for (i in vname) {if (i > indent) {delete vname[i]}}
      if (length($3) > 0) {
         vn=""; for (i=0; i<indent; i++) {vn=(vn)(vname[i])("_")}
         printf("%s%s%s=\"%s\"\n", "'$prefix'",vn, $2, $3);
      }
   }'
}

test.sh

#!/bin/sh

# include parse_yaml function
. parse_yaml.sh

# read yaml file
eval $(parse_yaml zconfig.yml "config_")

# access yaml content
echo $config_development_database

zconfig.yml

development:
  adapter: mysql2
  encoding: utf8
  database: my_database
  username: root
  password:

Hello,

niet now support eval output format so you can do things like that:

$ pip install -U niet
$ echo '{"foo-biz": "bar", "fizz": {"buzz": ["zero", "one", "two", "three"]}}' | niet -f eval .
 foo_biz="bar";fizz__buzz=( zero one two three )
$ eval $(echo '{"foo-biz": "bar", "fizz": {"buzz": ["zero", "one", "two", "three"]}}' | niet -f eval .)
$ echo ${foo_biz}
bar
$ echo ${fizz__buzz}
zero one two three
$ eval $(echo '{"foo-biz": "bar", "fizz": {"buzz": ["zero", "one", "two", "three"]}}' | niet -f eval '"foo-biz"'); echo ${foo_biz}
bar
$ echo '{"foo-biz": "bar", "fizz": {"buzz": ["zero", "one", "two", "three"]}}' | niet -f eval fizz.buzz
fizz_buzz=( zero one two three );
$ eval $(echo '{"foo-biz": "bar", "fizz": {"buzz": ["zero", "one", "two", "three"]}}' | niet -f eval fizz.buzz)
$ for el in ${fizz_buzz}; do echo $el; done
zero
one
two
three

niet work with JSON and YAML input, also you can convert each format to each other, just by using pip install -U niet.

Thank you. Can we validate that the username as below is mandatory and have value, non empty field. Right now it passed.
development:
adapter: mysql2
encoding: utf8
database: my_database
username:
if anyone tried, please share. Thanks much

https://github.com/jasperes/bash-yaml for impatient !

@pkuczynski, It's work for me as well to read the key in yaml file. Thanks for that. Do you have the script to replace the value after reading? i have to replace the each value which i reads .

Hi! What is the expected output from running test.sh? Perhaps listing an output file above would be useful.

Works great.

nice script!

Works really well, thank you!

description: sample message here
may overflow next line

I have a similar issue how could we store description variable that may overflow into the next line in the same

1_2_1_description="sample message here"
TO
1_2_1_description="sample message here may overflow next line"

Thank you!

I think python is superior in this scripting situation. why on earth anyone would use a bash script to do such a thing? python is generally pre-installed in mac and Linux.

python is so much clean and readable.

pip install pyyaml

---

import yaml

FILENAME = 'your_file.yml'

with open(FILENAME) as file:
    data:dict = yaml.full_load(file)

# data is a python dictionary

The traversal logic is super. Love it !! Sometimes its just fun to do these crazy stuff with Bash.

jq for JSON and yq for YAML
https://github.com/mikefarah/yq

Hi all! This is very interested thread. Anybody knows how to make it working where string spans several lines (through "|" pipe), example:

key1: |
   1st line
   2nd line
   3rd line
key2: |
   1st line
   2nd line
   3rd line

thanks for this.
added this to end after awk as a hack not to interpret $ interpolation (application: reading serverless.yml config into bash)

 | tr "$" "#" # don't want to interpret $

i cant figure out why its not running succesfully for me whenever i execute ./test.sh it gives me error
./test.sh
./test.sh: line 4: .: parse_yaml.sh: file not found
./test.sh: line 7: parse_yaml: command not found

has anybody else faced this issue please help

@Nigam8972 try with
. ./parse_yaml.sh
if they are in the same folder (it's what I use)

Cool, just discovered this; of course the more recent suggestions are more robust and feature-rich, but I found myself needing this on constrained (i.e. busybox, sh and no python) systems where going POSIX-sh only is the way to go.

The method here by @wadewegner (or similar) to pre-process problematic keys (but not their values) was the way to go, i.e. by using "advanced" sed hold-space etc.