On Mon, Sep 8, 2014 at 1:07 AM, Chet Ramey <chet.ra...@case.edu> wrote:
> On 9/4/14, 10:33 PM, Clark Wang wrote:
> > See following example:
> >
> > $ echo $BASH_VERSION
> > 4.3.18(1)-release
> > $ compgen -W 'hello hello' h
> > hello
> > hello
> > $
> >
> > It'll be good if only one "hello" is outputted.
>
> `complete' and `compgen' only generate lists of possible completions.
> Readline performs duplicate removal when it is deciding what to do
> with that list.
>
Thanks, Chet. I did not realized this.
In the following example I'll describe my use case and you can understand
why my requirement.
Many commands like ping and ssh would take a hostname as their parameter.
I'm trying to define a common compspec for all these commands since
bash-4.1 added the `complete -D' option which is very cool. My idea is just
like bash's builtin completion behavior when we input `@<TAB>' but I'd like
the `@' char to be automatically removed when there's only one host
matching. See following demo code:
function compgen_hosts
{
local cmd=$1
local cur=$2
local pre=$3
local -a hosts
local host
hosts=( $(awk '$1 !~ /^ *#/' /etc/hosts) )
if [[ $cur == @* ]]; then
host=${cur#*@}
COMPREPLY=( $( compgen -P @ -W "${hosts[*]}" "$host") )
fi
if [[ ${#COMPREPLY[@]} == 1 ]]; then
COMPREPLY[0]=${COMPREPLY[0]#@}
fi
}
complete -D -o nospace -F compgen_hosts
For most of the time this works fine. For example:
$ foo @host-<TAB><TAB>
@host-a.us @host-b.us
$ foo @host-a<TAB>
$ foo host-a.us
But there's a small problem because there are duplicate hostnames. For
example both `127.0.0.1` and `::1` are mapping to `localhost' and then my
code would not work:
$ foo @localhost<TAB><TAB>
@localhost
$
The reason is the `if [[ ${#COMPREPLY[@]} == 1 ]]' condition. For
`localhost' there are two candidates in COMPREPLY:
COMPREPLY=( localhost localhost )
I know I can manually remove duplicate entries (either when reading
/etc/hosts or from the output of compgen) but it would be convenient if the
result of compgen has already done that for me. :)
Thanks.
-clark
>
> Chet
>
> --
> ``The lyf so short, the craft so long to lerne.'' - Chaucer
> ``Ars longa, vita brevis'' - Hippocrates
> Chet Ramey, ITS, CWRU c...@case.edu
> http://cnswww.cns.cwru.edu/~chet/
>
