sed - Assign a header to multiple files, Linux -

a header file produced running main script , content changes anytime run program . want assign content of header file other 3 files header. content of other 3 files should not change except header. example file1

header content file1 content 

for file2

header content file2 content 

how done?

note: please consider program runs many times header must overwritten not many headers.

run code once preserve original files without header information:

for file in myfile1 myfile2 myfile3   cp ${file} ${file}.orig done 

run code every time header file changes

for file in myfile1 myfile2 myfile3   cat header ${file}.orig > ${file} done 

where myfile1, myfile2 , myfile3 3 original files referring , header file containing ever changing header information.