我有一个 shell 脚本，它执行一个带有从不同 Java 程序返回的参数的 Java 程序。
java -cp $wekaPath $(java GetFilter $WandFDir) -i $(pwd)/temp/training"$i"_$arffName.arff -o $(pwd)/temp/training_"$i"_$arffName.arff
回显时，它会产生以下字符串：
java -cp /home/robobenny/Documents/WEKA/weka-3-7-4/weka.jar weka.filters.supervised.attribute.AttributeSelection -E "weka.attributeSelection.InfoGainAttributeEval" -S "weka.attributeSelection.Ranker -T -1.7976931348623157E308 -N 20" -c first -i /home/robobenny/Documents/WEKA/Pipeline/temp/training1_Test.arff -o /home/robobenny/Documents/WEKA/Pipeline/temp/training_1_Test.arff
这很好，因为如果我将字符串复制到命令行，它会毫无意外地运行 Java 程序。当我不回显它并尝试从 shell 脚本执行它时，就会出现问题，我从终端得到以下信息：
<!-- language: lang-none -->
Can't find class called: "weka.attributeSelection.InfoGainAttributeEval"
Filter options:
-S <"Name of search class [search options]">
Sets search method for subset evaluators.
eg. -S "weka.attributeSelection.BestFirst -S 8"
-E <"Name of attribute/subset evaluation class [evaluator options]">
Sets attribute/subset evaluator.
eg. -E "weka.attributeSelection.CfsSubsetEval -L"
Options specific to evaluator weka.attributeSelection.CfsSubsetEval:
-M
Treat missing values as a separate value.
-L
Don't include locally predictive attributes.
Options specific to search weka.attributeSelection.BestFirst:
-P <start set>
Specify a starting set of attributes.
Eg. 1,3,5-7.
-D <0 = backward | 1 = forward | 2 = bi-directional>
Direction of search. (default = 1).
-N <num>
Number of non-improving nodes to
consider before terminating search.
-S <num>
Size of lookup cache for evaluated subsets.
Expressed as a multiple of the number of
attributes in the data set. (default = 1)
General options:
-h
Get help on available options.
(use -b -h for help on batch mode.)
-i <file>
The name of the file containing input instances.
If not supplied then instances will be read from stdin.
-o <file>
The name of the file output instances will be written to.
If not supplied then instances will be written to stdout.
-c <class index>
The number of the attribute to use as the class.
"first" and "last" are also valid entries.
If not supplied then no class is assigned.
当我硬编码$(java GetFilter $WandFDir)shell脚本中的输出时：
java -cp $wekaPath weka.filters.supervised.attribute.AttributeSelection -E "weka.attributeSelection.InfoGainAttributeEval" -S "weka.attributeSelection.Ranker -T -1.7976931348623157E308 -N 20" -c first -i $(pwd)/temp/training"$i"_$arffName.arff -o $(pwd)/temp/training_"$i"_$arffName.arff
它也正常运行。有趣的是，当回显时，双引号消失了。
java -cp /home/robobenny/Documents/WEKA/weka-3-7-4/weka.jar weka.filters.supervised.attribute.AttributeSelection -E weka.attributeSelection.InfoGainAttributeEval -S weka.attributeSelection.Ranker -T -1.7976931348623157E308 -N 20 -c first -i /home/robobenny/Documents/WEKA/Pipeline/temp/training2_Test.arff -o /home/robobenny/Documents/WEKA/Pipeline/temp/training_2_Test.arff
当我在输出中留下双引号时，出现$(java GetFilter $WandFDir)以下错误：
<!-- language: lang-none -->
Illegal options: -T -1.7976931348623157E308 -N 20
Filter options:
-S <"Name of search class [search options]">
Sets search method for subset evaluators.
eg. -S "weka.attributeSelection.BestFirst -S 8"
-E <"Name of attribute/subset evaluation class [evaluator options]">
Sets attribute/subset evaluator.
eg. -E "weka.attributeSelection.CfsSubsetEval -L"
Options specific to evaluator weka.attributeSelection.InfoGainAttributeEval:
-M
treat missing values as a seperate value.
-B
just binarize numeric attributes instead
of properly discretizing them.
Options specific to search weka.attributeSelection.Ranker:
-P <start set>
Specify a starting set of attributes.
Eg. 1,3,5-7.
Any starting attributes specified are
ignored during the ranking.
-T <threshold>
Specify a theshold by which attributes
may be discarded from the ranking.
-N <num to select>
Specify number of attributes to select
General options:
-h
Get help on available options.
(use -b -h for help on batch mode.)
-i <file>
The name of the file containing input instances.
If not supplied then instances will be read from stdin.
-o <file>
The name of the file output instances will be written to.
If not supplied then instances will be written to stdout.
-c <class index>
The number of the attribute to use as the class.
"first" and "last" are also valid entries.
If not supplied then no class is assigned.
我环顾四周，似乎找不到任何可以解决我问题的东西。