Copies or appends the contents of one file to another file
(vl-file-copy source-file destination-file [append])
Copy or append the contents of one file to another file. The vl-file-copy function will not overwrite an existing file; it will only append to it.
An integer, if the copy was successful; otherwise nil.
Some typical reasons for returning nil are
Copy autoexec.bat to newauto.bat:
_$ (vl-file-copy "c:/autoexec.bat" "c:/newauto.bat")
1417
_$ (vl-file-copy "c:/test.bat" "c:/newauto.bat")
nil
The copy fails because newauto.bat already exists, and the append argument was not specified.
Repeat the previous command, but specify append:
_$ (vl-file-copy "c:/test.bat" "c:/newauto.bat" T)
185
The copy is successful because T was specified for the append argument.