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
很难说,因为这取决于您希望解析器从YAML文档中提取什么。对于简单的情况,你可以使用grep、cut、awk等。对于更复杂的解析,您需要使用成熟的解析库,如Python的PyYAML或YAML::Perl。
其他回答
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
以下是Stefan Farestam回答的扩展版本:
function parse_yaml {
local prefix=$2
local s='[[:space:]]*' w='[a-zA-Z0-9_]*' fs=$(echo @|tr @ '\034')
sed -ne "s|,$s\]$s\$|]|" \
-e ":1;s|^\($s\)\($w\)$s:$s\[$s\(.*\)$s,$s\(.*\)$s\]|\1\2: [\3]\n\1 - \4|;t1" \
-e "s|^\($s\)\($w\)$s:$s\[$s\(.*\)$s\]|\1\2:\n\1 - \3|;p" $1 | \
sed -ne "s|,$s}$s\$|}|" \
-e ":1;s|^\($s\)-$s{$s\(.*\)$s,$s\($w\)$s:$s\(.*\)$s}|\1- {\2}\n\1 \3: \4|;t1" \
-e "s|^\($s\)-$s{$s\(.*\)$s}|\1-\n\1 \2|;p" | \
sed -ne "s|^\($s\):|\1|" \
-e "s|^\($s\)-$s[\"']\(.*\)[\"']$s\$|\1$fs$fs\2|p" \
-e "s|^\($s\)-$s\(.*\)$s\$|\1$fs$fs\2|p" \
-e "s|^\($s\)\($w\)$s:$s[\"']\(.*\)[\"']$s\$|\1$fs\2$fs\3|p" \
-e "s|^\($s\)\($w\)$s:$s\(.*\)$s\$|\1$fs\2$fs\3|p" | \
awk -F$fs '{
indent = length($1)/2;
vname[indent] = $2;
for (i in vname) {if (i > indent) {delete vname[i]; idx[i]=0}}
if(length($2)== 0){ vname[indent]= ++idx[indent] };
if (length($3) > 0) {
vn=""; for (i=0; i<indent; i++) { vn=(vn)(vname[i])("_")}
printf("%s%s%s=\"%s\"\n", "'$prefix'",vn, vname[indent], $3);
}
}'
}
该版本支持字典和列表的-符号和短符号。以下输入:
global:
input:
- "main.c"
- "main.h"
flags: [ "-O3", "-fpic" ]
sample_input:
- { property1: value, property2: "value2" }
- { property1: "value3", property2: 'value 4' }
产生如下输出:
global_input_1="main.c"
global_input_2="main.h"
global_flags_1="-O3"
global_flags_2="-fpic"
global_sample_input_1_property1="value"
global_sample_input_1_property2="value2"
global_sample_input_2_property1="value3"
global_sample_input_2_property2="value 4"
as you can see the - items automatically get numbered in order to obtain different variable names for each item. In bash there are no multidimensional arrays, so this is one way to work around. Multiple levels are supported. To work around the problem with trailing white spaces mentioned by @briceburg one should enclose the values in single or double quotes. However, there are still some limitations: Expansion of the dictionaries and lists can produce wrong results when values contain commas. Also, more complex structures like values spanning multiple lines (like ssh-keys) are not (yet) supported.
A few words about the code: The first sed command expands the short form of dictionaries { key: value, ...} to regular and converts them to more simple yaml style. The second sed call does the same for the short notation of lists and converts [ entry, ... ] to an itemized list with the - notation. The third sed call is the original one that handled normal dictionaries, now with the addition to handle lists with - and indentations. The awk part introduces an index for each indentation level and increases it when the variable name is empty (i.e. when processing a list). The current value of the counters are used instead of the empty vname. When going up one level, the counters are zeroed.
编辑:我已经为此创建了一个github存储库。
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" )
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
下面是一个bash-only解析器,利用sed和awk来解析简单的yaml文件:
function parse_yaml {
local prefix=$2
local s='[[:space:]]*' w='[a-zA-Z0-9_]*' fs=$(echo @|tr @ '\034')
sed -ne "s|^\($s\):|\1|" \
-e "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);
}
}'
}
它可以理解以下文件:
## global definitions
global:
debug: yes
verbose: no
debugging:
detailed: no
header: "debugging started"
## output
output:
file: "yes"
在解析时使用:
parse_yaml sample.yml
将输出:
global_debug="yes"
global_verbose="no"
global_debugging_detailed="no"
global_debugging_header="debugging started"
output_file="yes"
它也理解由ruby生成的yaml文件,其中可能包含ruby符号,例如:
---
:global:
:debug: 'yes'
:verbose: 'no'
:debugging:
:detailed: 'no'
:header: debugging started
:output: 'yes'
并将输出与前一个示例相同的结果。
脚本中的典型用法是:
eval $(parse_yaml sample.yml)
Parse_yaml接受一个前缀参数,这样导入的所有设置都有一个公共前缀(这将减少名称空间冲突的风险)。
parse_yaml sample.yml "CONF_"
收益率:
CONF_global_debug="yes"
CONF_global_verbose="no"
CONF_global_debugging_detailed="no"
CONF_global_debugging_header="debugging started"
CONF_output_file="yes"
注意,之前文件中的设置可以被后面的设置引用:
## global definitions
global:
debug: yes
verbose: no
debugging:
detailed: no
header: "debugging started"
## output
output:
debug: $global_debug
另一个很好的用法是先解析默认文件,然后解析用户设置,这是可行的,因为后一个设置会覆盖第一个设置:
eval $(parse_yaml defaults.yml)
eval $(parse_yaml project.yml)
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