Appending to Files, Viewing Files Read-Only, and Changing File Names in Vim

collecting lines of text into one file, you can use this command: > :write >> logfile This will write the text of the current file to the end of "logfile". Thus it is appended. This avoids that you have to copy the lines, edit the log file and put them there. Thus you save two steps. But you can only append to the end of a file. To append only a few lines, select them in Visual mode before typing ":write". In chapter 10 you will learn other ways to select a range of lines. ============================================================================== *07.6* Viewing a file Sometimes you only want to see what a file contains, without the intention to ever write it back. There is the risk that you type ":w" without thinking and overwrite the original file anyway. To avoid this, edit the file read-only. To start Vim in readonly mode, use this command: > vim -R file On Unix this command should do the same thing: > view file You are now editing "file" in read-only mode. When you try using ":w" you will get an error message and the file won't be written. When you try to make a change to the file Vim will give you a warning: W10: Warning: Changing a readonly file ~ The change will be done though. This allows for formatting the file, for example, to be able to read it easily. If you make changes to a file and forgot that it was read-only, you can still write it. Add the ! to the write command to force writing. If you really want to forbid making changes in a file, do this: > vim -M file Now every attempt to change the text will fail. The help files are like this, for example. If you try to make a change you get this error message: E21: Cannot make changes, 'modifiable' is off ~ You could use the -M argument to setup Vim to work in a viewer mode. This is only voluntary though, since these commands will remove the protection: > :set modifiable :set write ============================================================================== *07.7* Changing the file name A clever way to start editing a new file is by using an existing file that contains most of what you need. For example, you start writing a new program to move a file. You know that you already have a program that copies a file, thus you start with: > :edit copy.c You can delete the stuff you don't need. Now you need to save the file under a new name. The ":saveas" command can be used for this: > :saveas move.c Vim will write the file under the given name, and edit that file. Thus the next time you do ":write", it will write "move.c". "copy.c" remains unmodified. When you want to change the name of the file you are editing, but don't want to write the file, you can use this command: > :file move.c Vim will mark the file as "not edited". This means that Vim knows this is not the file you started editing. When you try to write the file, you might get this message: E13: File exists (use ! to override) ~ This protects you from accidentally overwriting another file. ============================================================================== Next chapter: |usr_08.txt| Splitting windows Copyright: see |manual-copyright| vim:tw=78:ts=8:noet:ft=help:norl:

This section covers three additional file-related tasks in Vim. It explains how to append the contents of the current file to another file using `:write >> logfile`. It describes opening a file in read-only mode using `vim -R file` or `view file` to prevent accidental modifications and how to override this. It also covers using `vim -M file` to completely disallow modifications. Finally, it details how to use `:saveas move.c` to save a copy of the current file under a new name and switch to editing the new file, and how to change the file name associated with the current buffer using `:file move.c` without saving the file, preventing accidental overwrites.