It is simple to copy all the sheets to other workbook with VBA code:
Sub CopyWorkbook()
Dim sh as Worksheet, wb as workbook
Set wb = workbooks("Target workbook")
For Each sh in workbooks("source workbook").Worksheets
sh.Copy After:=wb.Sheets(wb.sheets.count)
Next sh
End Sub
How can accomplish the same job with pure libreoffice basic code?
Cross posted on StackOverflow.
If you cross post, as a courtesy please let us know that you have done so, otherwise it leads to several discussions and a waste of time because several identical answers may be posted by different users.
Ah yes - user has a habit of removing their own posts when they find a solution.
Copy all worksheets in source file “/tmp/sample.ods” into target file “/tmp/new.ods”:
Sub Main
Dim FileProperties(0) As New com.sun.star.beans.PropertyValue
FileProperties(0).Name = "Hidden"
FileProperties(0).Value = true
Url_new = "private:factory/scalc"
set Target = StarDesktop.loadComponentFromURL(Url_new, "_blank", 0,FileProperties)
Path_source = "/tmp/sample.ods"
Url_source = ConvertToUrl(Path_source)
Source = StarDesktop.loadComponentFromURL(Url_source, "_blank", 0, FileProperties)
position = 0
For Each sheet In Source.Sheets
Target.sheets.importSheet(Source, sheet.Name, position)
position = position +1
Next
Path_target = "/tmp/new.ods"
Url_target = ConvertToUrl(Path_target)
Target.storeAsURL(Url_target,FileProperties)
End Sub
Help someone make it more shorter.
shorter 
cp /tmp/sample.ods /tmp/new.ods
With pure libreoffice basic ,instead of bash.
Copying all the sheets is the equivalent of copying the file, so why not just do that? A quick search with your favourite search engine would find FileCopy Statement.
This is not a solution to your problem; please delete it and re-post as a comment.