Re: gzip and gunzip should have -k (--keep) option like bzip2 and bunzip2

[Shriramana Sharma]

Bob Proulx wrote:
> Hmm...  Basic command line shell operation is not a trick.  Input and
>  output file redirection is a fundamental operation of the command
> line shell.  Most users learn that '>' redirects the output of a
> command to the file very early in their use of it.

Right. Now I have many gzipped files in a folder. How do I now gunzip
them all without destroying the gz files themselves? gunzip < *.gz
throws up an error saying "ambiguous redirect". It is evident that this
usage is straightforward, since I have to do one thing for a single file
and apparent another thing for many files.

> I can't believe this is typical however.  And now that you have 
> learned it you will have a new world of capability available to you.

OK thanks, but I still feel that this small addition would go a long way
to helping people using gzip. We should not force a new user into
learning < and > (especially when he/she is not used to the shell very
much) and whatever solution you are going to give me for the "ambiguous
redirect" up there just to do a small thing like zip or unzip files
without destroying the sources. Not all users will have the patience or
time to mail the list and get a reply. The -k option would really help
them.

See for example also, the tar command has the z and j options, whereas
the same work would be accomplished by tar -c | gzip and tar -c | bzip2.
Just because a more advanced alternative exists should not be a reason
not to provide a single simple alternative.

> Just because something can be done does not mean that it should be 
> done.  Duplicating code in multiple places can always be done but it 
> is almost always a bad idea to do so.  It creates a maintenance 
> problem to keep the code in sync with each other.

Just adding a few lines to say: "if there is an argument -k then do not
delete the original files" would create a maintenance problem with
syncing? For big libraries and things like that duplication is a
problem, but not with two-line solutions like -k.

> To avoid duplication of code and to provide consistency across 
> commands this functionality should be some place that is shared among
>  all of the commands.

Are you saying that -R for --recursive is implemented by the shell and
not commands like cp, chmod, chown individually? (All three use -R.)

Shriramana Sharma.