How to change file permission from within vi - vim

Question

I sometimes open a read-only file in vi, forgetting to do chmod +w before opening it. Is there way to change the file from within vi?
Something like !r chmod +w [filename]?
Is there a shortcut to refer to the currently open file without spelling it's long name?

Answer 1

Just use
:!chmod +w %
in command mode. % will be replaced by the current file name.

Answer 2

If you have the rights to write to the file, then you can just use exclamation mark to force it:
:w!
If you don't have the rights and need to change user, but still want to write to the file, sometimes you may go for something like
:w !sudo tee %

Answer 3

I know this is an old post, but with Vim Version8 a function has been included with which you can change file permissions.
According to the version8.txt file:
setfperm() set the permissions of a file
This function can then be called via the "call" command in Vim.
This is done as follows:
:call setfperm("file name","permissions")
The structure of the "permissions" string takes the same form as described in the Vim documentation:
getfperm({fname}) getfperm()
The result is a String, which is the read, write, and execute
permissions of the given file {fname}.
If {fname} does not exist or its directory cannot be read, an
empty string is returned.
The result is of the form "rwxrwxrwx", where each group of
"rwx" flags represent, in turn, the permissions of the owner
of the file, the group the file belongs to, and other users.
If a user does not have a given permission the flag for this
is replaced with the string "-". Example:
:echo getfperm("/etc/passwd")
This will hopefully (from a security point of view) display
the string "rw-r--r--" or even "rw-------".
A minimal example:
:call setfperm("foo.txt","rwxrwxrwx")
This adds read, write and execute permissions to the "foo.txt" file in the current directory.

Answer 4

Have you tried
!chmod +w %
The % represents the current filename.
You could also map a key to this like Ctrl-W.
:map <C-w> :!chmod +w %<CR>
Note that you type Ctrl-V Ctrl-M to get the <CR>

Answer 5

After editing your file with vim, press "esc" and then ":".
Then type the following command:
w !sudo tee %
Then press "Enter".
Then type
:q!
to successfully exit from the editor.

Answer 6

:!chmod <perms> <file>
and if vi still doesn't want to write it,
:se cpo-=W

Answer 7

As David pointed out, setfperm() is the way to do this within vim.
Here are the mappings I use to add write or execute permissions to the current file:
function! ChmodPlus(expr, pat)
let file = expand('%')
let oldperms = getfperm(file)
let newperms = substitute(oldperms, a:expr, a:pat, '')
if (oldperms != newperms)
call setfperm(file, newperms)
endif
echom(printf('Permissions: %s', newperms))
endfunction
function! ChmodPlusX()
call ChmodPlus('^\(..\).', '\1x')
endfunction
function! ChmodPlusW()
call ChmodPlus('^\(.\).', '\1w')
endfunction
" Make current file writeable
noremap <silent> <Leader>W :call ChmodPlusW()<CR>
" Make current file executable
noremap <silent> <Leader>X :call ChmodPlusX()<CR>

Answer 8

You can also do this with the netrw module that comes with vim if your lazy, example :Texplore followed by scrolling to the file in normal mode and entering gp. Octal or symbolic at least work.
It's a little more intuitive with multiple files but per buffer-window without, use your colon command history to repeat commands.