[gentoo-user] [OT] Kinda "try ... catch" in a shell script...how

[gentoo-user] [OT] Kinda "try ... catch" in a shell script...how

[tuxic]

Hi,

I have a coyple of files on my harddisk and on a mobile usb-disc.

Their names are of that pattern:

 something-<checksum>-something

where 'soemthing' can be totally different from file to file and
'<checksum>' is a checksum, which does not match the checksum of the
according file.

I want to delete the files on my harddisk, which has a '<checksum>'
which matches the '<checksum>' of the according file on the mobile 
harddisk.

The problem arises from a line of the shellscript I wrote.

    # code to extract the checksum from the file and put into
    # a variable named crc

    if [ -f <path to the mount point of the mobile disk>/*$crc* ] ; then

        # remove file on PC harddisk here

    fi

As soon the file is not found, the script ends with an 'Not found'
error, which '-f' is exactly for, because the expanding comes before
the '-f'...

So I need something else or a try-catch-thingy to make that work...but
how?

Or do I miss the forest for the trees here... ;)

Thanks a lot for the forest in advance!
Cheers
Meino

Re: [gentoo-user] [OT] Kinda "try ... catch" in a shell script...how

[Alexander Kapshuk]

On Sat, Mar 10, 2018 at 10:26 AM,  <tuxic@posteo.de> wrote:
> Hi,
>
> I have a coyple of files on my harddisk and on a mobile usb-disc.
>
> Their names are of that pattern:
>
>  something-<checksum>-something
>
> where 'soemthing' can be totally different from file to file and
> '<checksum>' is a checksum, which does not match the checksum of the
> according file.
>
> I want to delete the files on my harddisk, which has a '<checksum>'
> which matches the '<checksum>' of the according file on the mobile
> harddisk.
>
> The problem arises from a line of the shellscript I wrote.
>
>     # code to extract the checksum from the file and put into
>     # a variable named crc
>
>     if [ -f <path to the mount point of the mobile disk>/*$crc* ] ; then
>
>         # remove file on PC harddisk here
>
>     fi
>
> As soon the file is not found, the script ends with an 'Not found'
> error, which '-f' is exactly for, because the expanding comes before
> the '-f'...
>
> So I need something else or a try-catch-thingy to make that work...but
> how?
>
> Or do I miss the forest for the trees here... ;)
>
> Thanks a lot for the forest in advance!
> Cheers
> Meino
>
>
>
>
>

If you were using a loop, you could do something like this:
for file in /path/to/files
do test -f $file || continue
rm $file
done

Care to post the entire script, so we could probably come up with the
right solution for you?

Re: [gentoo-user] [OT] Kinda "try ... catch" in a shell script...how

[Stroller]

> On 10 Mar 2018, at 08:26, tuxic@posteo.de wrote:
> ...
> 
> As soon the file is not found, the script ends with an 'Not found'
> error, which '-f' is exactly for, because the expanding comes before
> the '-f'...
> 
> So I need something else or a try-catch-thingy to make that work...but
> how?
> 
> Or do I miss the forest for the trees here... ;)

I don't get that at all with this snippet:

  $ cat test.sh
  #!/bin/bash
  if [ -f foo* ] ; then
  echo "foo exists"
  fi
  $ 

This makes me suspect you've got `#!bash -x` (or -e?) as your first line, or something.

When you encounter a problem you don't understand, create the most minimal program you can to reproduce the problem. If you can't reproduce it, add to it one step at a time until it becomes what you're trying to do.

Stroller