R packages not found when scripts executed in shells but they are already installed and used in Rstudio

Background I am trying to run the Example Workflow in https://rki_bioinformatics.gitlab.io/ditasic/, in which example.sh is the major bash script that will take the example data (which is a bunch of sequences) and output some data matrices.

Moreover, the script requires both python and R. All the required packages in R ("optparse", "RcppCNPy", "AER") have been installed in R via the command 'install.packages()' and 'library()' in R studio.

Problem During the execution of example.sh in the command line, the following error messages are encountered:

Error in loadPackages(c("optparse", "RcppCNPy", "AER"), quietly = TRUE) : 
  missing R-package(s)optparseRcppCNPyAER
In addition: Warning messages:
1: In library(package, lib.loc = lib.loc, character.only = TRUE, logical.return = TRUE,  :
  there is no package called ‘optparse’
2: In library(package, lib.loc = lib.loc, character.only = TRUE, logical.return = TRUE,  :
  there is no package called ‘RcppCNPy’
3: In library(package, lib.loc = lib.loc, character.only = TRUE, logical.return = TRUE,  :
  there is no package called ‘AER’
Execution halted

But I am sure that the packages required have been installed, as I find the folders with the names of the packages in the library paths: /Library/Frameworks/R.framework/Versions/3.5/Resources/library.

Thus, what has happened that cause the program to issue such an error?