我希望提供一个结构化的配置文件，它对于非技术用户来说尽可能容易编辑(不幸的是它必须是一个文件)，所以我想使用YAML。然而，我找不到任何方法从Unix shell脚本解析这个。
当前回答
yq是一个轻量级、可移植的命令行YAML处理器
这个项目的目标是yaml文件的jq或sed。
(https://github.com/mikefarah/yq #自述)
作为示例(直接从文档中窃取)，给出一个示例。Yaml文件:
---
bob:
item1:
cats: bananas
item2:
cats: apples
then
yq eval '.bob.*.cats' sample.yaml
将输出
- bananas
- apples
其他回答
如果您知道您感兴趣的标记和您期望的yaml结构，那么在Bash中编写一个简单的yaml解析器并不难。
在下面的示例中，解析器将一个结构化YAML文件读入环境变量、数组和关联数组。
注意:这个解析器的复杂性与YAML文件的结构有关。对于YAML文件的每个结构化组件，都需要一个单独的子例程。高度结构化的YAML文件可能需要更复杂的方法，例如通用的递归下降解析器。
圣诞节。yaml文件:
# Xmas YAML example
---
# Values
pear-tree: partridge
turtle-doves: 2.718
french-hens: 3
# Array
calling-birds:
- huey
- dewey
- louie
- fred
# Structure
xmas-fifth-day:
calling-birds: four
french-hens: 3
golden-rings: 5
partridges:
count: 1
location: "a pear tree"
turtle-doves: two
解析器使用mapfile将文件作为数组读入内存，然后循环遍历每个标记并创建环境变量。
梨树、斑鸠和法国母鸡:最终成为简单的环境变量 呼叫鸟:变成一个数组 xmas-fifth-day:结构被表示为一个关联数组，但是如果您没有使用Bash 4.0或更高版本，您可以将这些数组编码为环境变量。 注释和空白将被忽略。
#!/bin/bash
# -------------------------------------------------------------------
# A simple parser for the xmas.yaml file
# -------------------------------------------------------------------
#
# xmas.yaml tags
# # - Ignored
# - Blank lines are ignored
# --- - Initialiser for days-of-xmas
# pear-tree: partridge - a string
# turtle-doves: 2.718 - a string, no float type in Bash
# french-hens: 3 - a number
# calling-birds: - an array of strings
# - huey - calling-birds[0]
# - dewey
# - louie
# - fred
# xmas-fifth-day: - an associative array
# calling-birds: four - a string
# french-hens: 3 - a number
# golden-rings: 5 - a number
# partridges: - changes the key to partridges.xxx
# count: 1 - a number
# location: "a pear tree" - a string
# turtle-doves: two - a string
#
# This requires the following routines
# ParseXMAS
# parses #, ---, blank line
# unexpected tag error
# calls days-of-xmas
#
# days-of-xmas
# parses pear-tree, turtle-doves, french-hens
# calls calling-birds
# calls xmas-fifth-day
#
# calling-birds
# elements of the array
#
# xmas-fifth-day
# parses calling-birds, french-hens, golden-rings, turtle-doves
# calls partridges
#
# partridges
# parses partridges.count, partridges.location
#
function ParseXMAS()
{
# days-of-xmas
# parses pear-tree, turtle-doves, french-hens
# calls calling-birds
# calls xmas-fifth-day
#
function days-of-xmas()
{
unset PearTree TurtleDoves FrenchHens
while [ $CURRENT_ROW -lt $ROWS ]
do
LINE=( ${CONFIG[${CURRENT_ROW}]} )
TAG=${LINE[0]}
unset LINE[0]
VALUE="${LINE[*]}"
echo " days-of-xmas[${CURRENT_ROW}] ${TAG}=${VALUE}"
if [ "$TAG" = "pear-tree:" ]
then
declare -g PearTree=$VALUE
elif [ "$TAG" = "turtle-doves:" ]
then
declare -g TurtleDoves=$VALUE
elif [ "$TAG" = "french-hens:" ]
then
declare -g FrenchHens=$VALUE
elif [ "$TAG" = "calling-birds:" ]
then
let CURRENT_ROW=$(($CURRENT_ROW + 1))
calling-birds
continue
elif [ "$TAG" = "xmas-fifth-day:" ]
then
let CURRENT_ROW=$(($CURRENT_ROW + 1))
xmas-fifth-day
continue
elif [ -z "$TAG" ] || [ "$TAG" = "#" ]
then
# Ignore comments and blank lines
true
else
# time to bug out
break
fi
let CURRENT_ROW=$(($CURRENT_ROW + 1))
done
}
# calling-birds
# elements of the array
function calling-birds()
{
unset CallingBirds
declare -ag CallingBirds
while [ $CURRENT_ROW -lt $ROWS ]
do
LINE=( ${CONFIG[${CURRENT_ROW}]} )
TAG=${LINE[0]}
unset LINE[0]
VALUE="${LINE[*]}"
echo " calling-birds[${CURRENT_ROW}] ${TAG}=${VALUE}"
if [ "$TAG" = "-" ]
then
CallingBirds[${#CallingBirds[*]}]=$VALUE
elif [ -z "$TAG" ] || [ "$TAG" = "#" ]
then
# Ignore comments and blank lines
true
else
# time to bug out
break
fi
let CURRENT_ROW=$(($CURRENT_ROW + 1))
done
}
# xmas-fifth-day
# parses calling-birds, french-hens, golden-rings, turtle-doves
# calls fifth-day-partridges
#
function xmas-fifth-day()
{
unset XmasFifthDay
declare -Ag XmasFifthDay
while [ $CURRENT_ROW -lt $ROWS ]
do
LINE=( ${CONFIG[${CURRENT_ROW}]} )
TAG=${LINE[0]}
unset LINE[0]
VALUE="${LINE[*]}"
echo " xmas-fifth-day[${CURRENT_ROW}] ${TAG}=${VALUE}"
if [ "$TAG" = "calling-birds:" ]
then
XmasFifthDay[CallingBirds]=$VALUE
elif [ "$TAG" = "french-hens:" ]
then
XmasFifthDay[FrenchHens]=$VALUE
elif [ "$TAG" = "golden-rings:" ]
then
XmasFifthDay[GOLDEN-RINGS]=$VALUE
elif [ "$TAG" = "turtle-doves:" ]
then
XmasFifthDay[TurtleDoves]=$VALUE
elif [ "$TAG" = "partridges:" ]
then
let CURRENT_ROW=$(($CURRENT_ROW + 1))
partridges
continue
elif [ -z "$TAG" ] || [ "$TAG" = "#" ]
then
# Ignore comments and blank lines
true
else
# time to bug out
break
fi
let CURRENT_ROW=$(($CURRENT_ROW + 1))
done
}
function partridges()
{
while [ $CURRENT_ROW -lt $ROWS ]
do
LINE=( ${CONFIG[${CURRENT_ROW}]} )
TAG=${LINE[0]}
unset LINE[0]
VALUE="${LINE[*]}"
echo " partridges[${CURRENT_ROW}] ${TAG}=${VALUE}"
if [ "$TAG" = "count:" ]
then
XmasFifthDay[PARTRIDGES.COUNT]=$VALUE
elif [ "$TAG" = "location:" ]
then
XmasFifthDay[PARTRIDGES.LOCATION]=$VALUE
elif [ -z "$TAG" ] || [ "$TAG" = "#" ]
then
# Ignore comments and blank lines
true
else
# time to bug out
break
fi
let CURRENT_ROW=$(($CURRENT_ROW + 1))
done
}
# ===================================================================
# Load the configuration file
mapfile CONFIG < xmas.yaml
let ROWS=${#CONFIG[@]}
let CURRENT_ROW=0
# +
# #
#
# ---
# -
while [ $CURRENT_ROW -lt $ROWS ]
do
LINE=( ${CONFIG[${CURRENT_ROW}]} )
TAG=${LINE[0]}
unset LINE[0]
VALUE="${LINE[*]}"
echo "[${CURRENT_ROW}] ${TAG}=${VALUE}"
if [ "$TAG" = "---" ]
then
let CURRENT_ROW=$(($CURRENT_ROW + 1))
days-of-xmas
continue
elif [ -z "$TAG" ] || [ "$TAG" = "#" ]
then
# Ignore comments and blank lines
true
else
echo "Unexpected tag at line $(($CURRENT_ROW + 1)): <${TAG}>={${VALUE}}"
break
fi
let CURRENT_ROW=$(($CURRENT_ROW + 1))
done
}
echo =========================================
ParseXMAS
echo =========================================
declare -p PearTree
declare -p TurtleDoves
declare -p FrenchHens
declare -p CallingBirds
declare -p XmasFifthDay
这将产生以下输出
=========================================
[0] #=Xmas YAML example
[1] ---=
days-of-xmas[2] #=Values
days-of-xmas[3] pear-tree:=partridge
days-of-xmas[4] turtle-doves:=2.718
days-of-xmas[5] french-hens:=3
days-of-xmas[6] =
days-of-xmas[7] #=Array
days-of-xmas[8] calling-birds:=
calling-birds[9] -=huey
calling-birds[10] -=dewey
calling-birds[11] -=louie
calling-birds[12] -=fred
calling-birds[13] =
calling-birds[14] #=Structure
calling-birds[15] xmas-fifth-day:=
days-of-xmas[15] xmas-fifth-day:=
xmas-fifth-day[16] calling-birds:=four
xmas-fifth-day[17] french-hens:=3
xmas-fifth-day[18] golden-rings:=5
xmas-fifth-day[19] partridges:=
partridges[20] count:=1
partridges[21] location:="a pear tree"
partridges[22] turtle-doves:=two
xmas-fifth-day[22] turtle-doves:=two
=========================================
declare -- PearTree="partridge"
declare -- TurtleDoves="2.718"
declare -- FrenchHens="3"
declare -a CallingBirds=([0]="huey" [1]="dewey" [2]="louie" [3]="fred")
declare -A XmasFifthDay=([CallingBirds]="four" [PARTRIDGES.LOCATION]="\"a pear tree\"" [FrenchHens]="3" [GOLDEN-RINGS]="5" [PARTRIDGES.COUNT]="1" [TurtleDoves]="two" )
我已经用python编写了shyaml，用于从shell命令行查询YAML。
概述:
$ pip install shyaml ## installation
示例的YAML文件(具有复杂的功能):
$ cat <<EOF > test.yaml
name: "MyName !!"
subvalue:
how-much: 1.1
things:
- first
- second
- third
other-things: [a, b, c]
maintainer: "Valentin Lab"
description: |
Multiline description:
Line 1
Line 2
EOF
基本的查询:
$ cat test.yaml | shyaml get-value subvalue.maintainer
Valentin Lab
更复杂的循环查询复杂的值:
$ cat test.yaml | shyaml values-0 | \
while read -r -d $'\0' value; do
echo "RECEIVED: '$value'"
done
RECEIVED: '1.1'
RECEIVED: '- first
- second
- third'
RECEIVED: '2'
RECEIVED: 'Valentin Lab'
RECEIVED: 'Multiline description:
Line 1
Line 2'
以下几个要点:
all YAML types and syntax oddities are correctly handled, as multiline, quoted strings, inline sequences... \0 padded output is available for solid multiline entry manipulation. simple dotted notation to select sub-values (ie: subvalue.maintainer is a valid key). access by index is provided to sequences (ie: subvalue.things.-1 is the last element of the subvalue.things sequence.) access to all sequence/structs elements in one go for use in bash loops. you can output whole subpart of a YAML file as ... YAML, which blend well for further manipulations with shyaml.
更多的示例和文档可以在shyaml github页面或shyaml PyPI页面上找到。
我的用例可能与这篇原始文章所要求的完全相同，也可能不完全相同，但它肯定是相似的。
我需要拉一些YAML作为bash变量。YAML的深度永远不会超过一层。
YAML看起来是这样的:
KEY: value
ANOTHER_KEY: another_value
OH_MY_SO_MANY_KEYS: yet_another_value
LAST_KEY: last_value
输出如下:
KEY="value"
ANOTHER_KEY="another_value"
OH_MY_SO_MANY_KEYS="yet_another_value"
LAST_KEY="last_value"
我用这一行实现了输出:
sed -e 's/:[^:\/\/]/="/g;s/$/"/g;s/ *=/=/g' file.yaml > file.sh
s/:[^:\/\/]/="/g查找:并将其替换为="，同时忽略://(对于url) S /$/"/g将"附加到每一行的末尾 S / *=/=/g删除=前面的所有空格
考虑到Python3和PyYAML是非常容易满足的依赖关系，下面的代码可能会有所帮助:
yaml() {
python3 -c "import yaml;print(yaml.safe_load(open('$1'))$2)"
}
VALUE=$(yaml ~/my_yaml_file.yaml "['a_key']")
可以将一个小脚本传递给一些解释器，比如Python。使用Ruby和它的YAML库的简单方法如下:
$ RUBY_SCRIPT="data = YAML::load(STDIN.read); puts data['a']; puts data['b']"
$ echo -e '---\na: 1234\nb: 4321' | ruby -ryaml -e "$RUBY_SCRIPT"
1234
4321
，其中data是来自yaml的值的散列(或数组)。
作为奖励，它可以很好地解析杰基尔的正面问题。
ruby -ryaml -e "puts YAML::load(open(ARGV.first).read)['tags']" example.md
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