Ubuntu Caesar Cipher加密/解密失败

Question

我已经完成了将字符替换为字符的练习，

library(caret)
library(dslabs)
set.seed(1)
data("mnist_27")

models <- c("glm", "lda",  "naive_bayes",  "svmLinear", 
            "gamboost",  "gamLoess", "qda", 
            "knn", "kknn", "loclda", "gam",
            "rf", "ranger",  "wsrf", "Rborist", 
            "avNNet", "mlp", "monmlp",
            "adaboost", "gbm",
            "svmRadial", "svmRadialCost", "svmRadialSigma")

fits <- lapply(models, function(model){ 
  print(model)
  train(y ~ ., method = model, data = mnist_27$train)
}) 

names(fits) <- models

fits_predicts <- sapply(fits, function(fits){ predict(fits,mnist_27$test)
  })

然后我像这样进行解密：

Cat xxxxxx | tr [a-z]  [d-zabc] | tr [A-Z]  [D-ZABC]  > xxxxxx_cesar

并且效果很好，然后我尝试用字符替换元音，加密有效，而解密无效。

加密：

Cat xxxxxx | tr [d-zabc]  [a-z] | tr [D-ZABC]  [A-Z]  > xxxxxx_cesar

解密：

Cat xxxxxx | tr [aeiou]  [:_,.-] | tr [AEIOU] [:_,.-]  > xxxxxx_sustitu