Re: stat(1) print formats

[Pádraig Brady]

On 21/11/14 17:24, David Braun wrote:
> I'd like to argue that the output from the %N format from the stat(1)
> command is flawed for several reasons.
> 
> 1. The use of left and right quotes is counter to tradition and complicates
> any shell post processing of the output. All shells that I'm familiar with
> use paired quotes (left, right or double). Mixing them become difficult to
> deal with.

That's been changed for quite a while with:
http://git.sv.gnu.org/gitweb/?p=gnulib.git;a=commitdiff;h=1a43a98

> 2. The use of quotes only occurs for the %N format and is only necessary
> because of the "xxx -> yyy" result because of the possibility of special
> characters in either of the xxx or yyy portions.
> 
> If instead %N merely produces the link value (the yyy part) without quotes
> (as for the %n format) then the user of the stat command has the option of
> formating the result any why she wants - almost.

I think that request is already covered in
http://bugs.gnu.org/18625

> Assume for the examples below that the following two files exist
> 
> $ ls -l
> total 0
> lrwxrwxrwx 1 vrams vrams 11 2014-11-21 11:34 LinkToFile -> regularFile
> -rw-r--r-- 1 vrams vrams  0 2014-11-21 11:34 regularFile
> 
> 
> The current behavior of the stat command will produce the following
> 
> 
> $ stat -c "file(%n) link(%N)" regularFile
> file(regularFile) link(`regularFile')
> 
> $ stat -c "file(%n) link(%N)" LinkToFile
> file(LinkToFile) link(`LinkToFile' -> `regularFile')
> 
> 
> but if %N instead just produced the unadorned link value the result would be
> 
> $ stat -c "file(%n) link(%N)" regularFile
> file(regularFile) link(regularFile)
> 
> $ stat -c "file(%n) link(%N)" LinkToFile
> file(LinkToFile) link(regularFile)
> 
> 
> If the user wanted to use quotes instead of parens as above she could
> 
> $ stat -c "file = '%n'    link = '%N'" regularFile
> file = 'regularFile'    link = 'regularFile'
> 
> $ stat -c "file = '%n'    link = '%N'" LinkToFile
> file = 'LinkToFile'     link = 'regularFile'
> 
> 
> or even reproduce the current behavior (almost) with
> 
> $ stat -c "file = '%n' link = '%n' -> '%N'" LinkToFile
> file = 'LinkToFile'    link = 'LinkToFile' -> 'regularFile'
> 
> 
> I say "almost" because the above example applied to regularfile will produce
> 
> $ stat -c "file = '%n' link = '%n' -> '%N'" regularFile
> file = 'regularFile'    link = 'regularFile' -> 'regularFile'
> 
> 
> Which is different than current behavior and is difficult to differentiate
> from an self referencing symbolic link (you can create them but not use
> them for much).
> 
> (You'll also notice I have gotten rid of that annoying left/right quoting
> ... garbage in the above - paired quotes are much easier to deal with.)
> 
> For this reason and to maintain backward compatibility maybe it would be
> better to introduce another format specifier (%L maybe) defined as
> producing an unadorned link value (no quotes or "->" stuff) or file name if
> not a symbolic link similar in formatting to %n. Alternatively a flag
> argument ('-l' perhaps) could be introduced that causes %N to produce the
> unadorned link value.
> 
> Or as yet another alternative, since '-t' has no current effect when '-c'
> is used to format output, maybe it could serve to modify the output of %N
> to be the unadorned link value.
> 
> By the way - there doesn't seem to be any documentation for the output
> resulting from the use of '-t'.

That's fixed already:
http://git.sv.gnu.org/gitweb/?p=coreutils.git;a=commitdiff;h=b020002b

thanks,
Pádraig.