Re: [PLUG] Interactive rm

Art Alexion <art.alexion@verizon.net> · 2006年2月01日 14:44:57 -0500

bergman@merctech.com wrote:
>the original posted requested a slightly 
>different behavior, as in:
>	if there are multiple arguments to rm, then run rm interactively
>	if there is a single argument to rm, then run rm non-interactively
>
>This is not as trivial as it appears. While it's easy to count the number of 
>arguments and call "rm -i" if there's more than one argument, this doesn't deal 
>correctly with arguments that are options, not the targets of the rm command. 
>In addition, rm is sensitive to the order of arguments, and it's easy to get 
>unexpected results when combining "-f" and "-i". I'm also skipping over the 
>issues with targets that have embedded whitespace in their names...
>
>=> > How can I restore rm's default behavior so that "rm *" requires
>=> > confirmation, but "rm specified_file" does not?
>
>Here's a bash shell function that will do what you want. This fragment of code 
>can be put in your ~/.bashrc file. Note that the function, as named, will work 
>when called as "myrm". You can change this to "rm" and therefore hide how "rm" 
>really behaves.
> 
>
Thank you Mark. That does the trick. A couple of test yield the
following, though:
 * it seems, as written, it is called with 'saferm', not 'myrm', right?
 * though it doesn't treat options as file arguments, it does not
 pass the options to rm, so 'saferm -f *' still runs rm as 'rm -i *'
 * I wanted to rename it just 'rm', but then presumed that the 'rm
 wildcard' stuff in some of my scripts would start to require
 confirmation which I could not force with 'rm -f wildcard'
 * I knew it would be tough to change my habit of just typing rm to
 typing saferm (and the evil I am trying to avoid is habit driven),
 so I renamed it 'del' as in DOS del (I often type rm in a win
 command shell as it is) which is just regaining an old habit.
 * a weird observation. I have three shells open. I did my
 experiments with one of the shells only, i.e. I only ran the
 command 'source ~/.bashrc' in one of the shells. In that shell, I
 ran the function after renaming it 'rm'. After I found out that
 'rm -f *.flub' no longer overrode the -i option, I changed the
 name to del and ran 'source ~/.bashrc' again. But in that shell,
 rm still asks for confirmation, even though del works, too. In
 the other shells, I only ran the source command only after I was
 done editing, and rm works as it does by default.
 * You are right that it doesn't work with files with embedded spaces.
Thanks, again. I really appreciate the help.
 
>------------------------------------------------------------------------------
>function saferm
>{
> # Shell function to call rm interactively if there are multiple
> # non-option arguments to rm. This is somewhat complicated due
> # to the need to separate option arguments from targets,
> # and for the need to deal with the special case of the "--"
> # argument.
> #
> # $Header: /home/bergman/Bin/RCS/saferm,v 1.2 2006年02月01日 18:11:57 bergman Exp bergman $
> #
> # Copyright 2006, Mark Bergman
> # bergman@merctech.com
> # Released under the GNU GENERAL PUBLIC LICENSE, Version 2
> targetcount=0
> targets=""
> options=""
>
> for arg in $*
> do
> case $arg in
> --)
> # signifier of last option argument,
> # successive filename arguments may begin with
> # a "-", so copy all remaining arguments into the
> # list of targets
> temp=`echo $* | sed -e "s/.* -- //"`
> targets="$targets $temp"
> targetcount=$((targetcount + 1))
> last
> ;;
>
> -*)
> # We have an option argument...
> options="$options $arg"
> ;;
>
> *)
> # non-option argument...copy it into the
> # list of file/directory names
> #
> # Note: this will probably break (badly)
> # if used with filenames with embedded
> # whitespace. It's possible to munge IFS
> # to get around some of that...
> targets="$targets $arg"
> targetcount=$((targetcount + 1))
> ;;
> esac
> done
>
> if [ $targetcount -gt 1 ]
> then
> # Note: this weirdness is due to the fact that rm applies
> # option arguments in the order that they are found, with
> # successive arguments overriding previous ones. Thus, if
> # one of the arguments is "-f" (force non- interactive),
> # then the "-i" must be the last argument
>
> /bin/rm $options -i $targets
> else
> /bin/rm $*
> fi
>}
>
>------------------------------------------------------------------------------
>Mark
> 
>
-- 
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