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@briantjacobs
Created November 24, 2015 19:43
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Parse YAML from bash with sed and awk.
development:
adapter: mysql2
encoding: utf8
database: my_database
username: root
password:
apt:
- somepackage
- anotherpackage
development_adapter=("mysql2")
development_encoding=("utf8")
development_database=("my_database")
development_username=("root")
development_apt+=("somepackage")
development_apt+=("anotherpackage")
#!/usr/bin/env bash
#
# vim: set ft=sh:
#
# Based on https://gist.github.com/pkuczynski/8665367
parse_yaml() {
local prefix=$2
local s
local w
local fs
s='[[:space:]]*'
w='[a-zA-Z0-9_]*'
fs="$(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);
}
}' | sed 's/_=/+=/g'
}
parse_yaml config.yml
@phiarchitect
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this is ingenious.

@chrisbergeron
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How can I convert the prefix to uppercase (toupper) using printf in awk? Sorry, awk is not my strong suit.
I tried using a bash builtin ${string^^} but it doesn't work within the awk print.

@sf-thomasblanchard
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sf-thomasblanchard commented Jan 16, 2023

How can I convert the prefix to uppercase (toupper) using printf in awk? Sorry, awk is not my strong suit. I tried using a bash builtin ${string^^} but it doesn't work within the awk print.

Suggestion 1: use awk's toupper (respect. tolower) functions

printf("%s%s%s=(\"%s\")\n", "'"$prefix"'",vn, toupper($2), $3);

Suggestion 2: create a separate prefix variable all uppercase (not tested, ymmv)

local prefix=${2}
local prefix_upper=${2^^}

[...]
printf("%s%s%s=(\"%s\")\n", "'"$prefix_upper"'",vn, $2, $3);

@chrisbergeron
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The first suggestion works. The second didn't (macos awk). Thank you!

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