Question

I am running the IBAMR model (a set of codes for solving immersed boundary problems) on x86_64 GNU/Linux.
The startup configuration file is called input2d.
When I open it with vi, I find:

“input2d” [noeol][dos] 251L, 11689C

If I compile the IBAMR model without saving input2d, it compiles and runs fine.
However, if I save input2d, the compiler crashes, saying:

Warning in input2d at line 251 column 5 : Illegal character token in input

Clearly this has something to do with unix adding a newline to the end of the file.
Here’s my question:
How do I save this file in dos format AND without a trailing newline in vi on a unix system?

Answer 1

Use vim -b <file> or :set binary to tell vim not to append an newline at the end of the file. From :help binary:

When writing a file the <EOL> for the last line is only written if
there was one in the original file (normally Vim appends an <EOL> to
the last line if there is none; this would make the file longer). See
the ‘endofline’ option.