[ale] Bash parameter expansions

[Alex Carver]

Yep, that's exactly what I did to test your suggestion which does work. 
  I need to check the same input against the echo statement itself which 
does need to print quotes around it but I think I've got that working 
with a variant of your alt-text implementation.

On 2022-02-16 08:16, Scott Plante via Ale wrote:
> It occurred to me that I was printing the command line you were looking
> for, but printing it is not really what you're after. You want to call the
> command with the parameters grouped in the right positional parameter
> spots. To test for that, I make a fake ipset function that just prints it's
> parameters as it sees them. I wasn't keen to actually run ipset but I think
> this now works the way you want:
> 
> ipset()
> {
>   echo ipset: params
>   echo '$1='"$1"
>   echo '$2='"$2"
>   echo '$3='"$3"
>   echo '$4='"$4"
>   echo '$5='"$5"
>   echo '$6='"$6"
> }
> 
> ipset add "$1" "$2" ${3:+commment "${*:3}"}
> 
> splante at guinness:/tmp/> ./addip.sh test 100.0.0.0/32
> ipset: params
> $1=add
> $2=test
> $3=100.0.0.0/32
> $4=
> $5=
> $6=
> splante at guinness:/tmp/> ./addip.sh test 100.0.0.0/32 My    Comment    No
>    Quotes
> ipset: params
> $1=add
> $2=test
> $3=100.0.0.0/32
> $4=commment
> $5=My Comment No Quotes
> $6=
> splante at guinness:/tmp/> ./addip.sh test 100.0.0.0/32 "My    Comment    With
>    Quotes"
> ipset: params
> $1=add
> $2=test
> $3=100.0.0.0/32
> $4=commment
> $5=My    Comment    With   Quotes
> $6=
> 
> You'd just remove the ipset function and change the call to /sbin/ipset
> 
> Scott
> 
> On Tue, Feb 15, 2022 at 2:37 PM Scott Plante <splante at insightsys.com> wrote:
> 
>> How about this?
>>
>> splante at guinness:/tmp/> cat ./addip.sh
>> #!/bin/bash
>>
>> echo add "$1" "$2" ${3:+commment \""${@:3}"\"}
>>
>> splante at guinness:/tmp/> ./addip.sh test 100.0.0.0/32
>> add test 100.0.0.0/32
>> splante at guinness:/tmp/> ./addip.sh test 100.0.0.0/32 my comment
>> add test 100.0.0.0/32 commment "my comment"
>> splante at guinness:/tmp/> ./addip.sh test 100.0.0.0/32 "my    comment
>>    with   spaces"
>> add test 100.0.0.0/32 commment "my    comment   with   spaces"
>>
>> You even get the option of using quotes for space preservation  in the
>> comment, but you only need to quote the comment for that case.
>>
>> Obviously you need to add your call to ipset and whatever parameter
>> checking and logging you need, but does that work for the expansion
>> question?
>>
>> Scott Plante
>>
>> On Sun, Feb 13, 2022 at 5:50 PM Alex Carver via Ale <ale at ale.org> wrote:
>>
>>> I'm putting a tiny utility script together to make it faster for me to
>>> update ipset lists and add them to a restore file in one shot but I've
>>> run into a slight hiccup with what I wanted to accomplish.
>>>
>>> So in the ideal case the script is called like this:
>>>
>>> addip.sh listname cidr [multiple word comment]
>>>
>>> The key is the multiple word comment which I wanted to be lazy and not
>>> have to type in quotation marks around it.  No problem for that, I just
>>> gather up anything on the command line after the second parameter:
>>>
>>> comment="${*:3}"
>>>
>>> The problem is when I'm trying to pass this to both ipset and to
>>> concatenate to the end of a file.  The call to ipset would be:
>>>
>>> ipset add ${1} ${2} {$comment:+comment} ${comment}
>>>
>>> and appending to file would be:
>>>
>>> echo add ${1} ${2} {$comment:+comment}
>>> ${comment:+\"}${comment}${comment:+\"} >> savefile
>>>
>>>
>>> The ipset command uses the alternate text expansion to put the literal
>>> word 'comment' on the command line if $comment is not empty.  The echo
>>> command does something similar and also uses that same method to wrap
>>> the text in double quotes if it's not null (this is to avoid having
>>> 'comment ""' in the save line).
>>>
>>> The problem is the comment variable on the ipset line.  If I call my
>>> script with no comments (addip.sh list ip) then it executes ipset just
>>> fine and the file gets a copy of the entry with no comment added.
>>>
>>> But if I call it with the addition of a comment, ipset sees an extra
>>> parameter at the end of it's command line and complains with an unknown
>>> argument error:
>>>
>>> addip.sh test 100.0.0.0/32 This is my comment
>>> ipset: Unknown argument: 'is'
>>>
>>> Ok, so normally I would think to do something like this:
>>>
>>> ipset add ${1} ${2} {$comment:+comment} "${comment}"
>>>
>>> But that then breaks the condition where no comment is desired. In this
>>> case I get an unknown argument error again but for an empty one:
>>>
>>> addip.sh test 100.0.0.0/32
>>> ipset: Unknown argument: ''
>>>
>>> I was trying to set up the script to have ipset called in only one place
>>> instead of calling it twice using an if/else block but I can't quite
>>> figure out how to get the parameter expansion to work for both cases.
>>>
>>> Plus whatever I do has to also satisfy the echo statement to produce one
>>> of these two strings to append to the file depending whether there's
>>> comments or not:
>>>
>>> add test 10.0.0.0/32
>>> add test 10.0.0.0/32 comment "This is my comment"
>>>
>>> Thoughts?
>>> _______________________________________________
>>> Ale mailing list
>>> Ale at ale.org
>>> https://mail.ale.org/mailman/listinfo/ale
>>> See JOBS, ANNOUNCE and SCHOOLS lists at
>>> http://mail.ale.org/mailman/listinfo
>>>
>>>
> 
> 
> _______________________________________________
> Ale mailing list
> Ale at ale.org
> https://mail.ale.org/mailman/listinfo/ale
> See JOBS, ANNOUNCE and SCHOOLS lists at
> http://mail.ale.org/mailman/listinfo