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From: Nix on 13 Mar 2010 11:13
On 12 Mar 2010, Mark Hobley spake thusly:

> Some of use the terms differently, but I would interpret a bashism as being
> any syntax element that is not supported in the System V Unix shell. So a
> kshism may also be called a bashism.

I call things bashisms if they're supported by bash but not other major
shells (bar zsh, which supports everything), in particular the shell
defined by POSIX.

I don't give a damn about the System V Unix shell per se anymore. Nobody
uses it.
From: Folderol on 13 Mar 2010 13:09
On 12 Mar 2010 22:05:31 GMT
"Chris F.A. Johnson" <cfajohnson(a)gmail.com> wrote:

> On 2010-03-12, Folderol wrote:
> > The script below works perfectly in bash, but if I try to run it on a
> > system with dash I get the following error:
> >
> > Start_Midisport.sh: 21: [[: not found
>
> Dash is a very basic POSIX shell. [[ ... ]] is not part of the
> POSIX shell.
>
> > Can anyone suggest what I should do to get it to work equally well in
> > either shell?
> >
> >
> > #!/bin/bash
> >
> > # echo's can be removed -just for testing
> >
> > name="MidiSport"
> > lsusb | cat | while read line
>
> Why do you have 'cat' in there?
>
> > do
> > if [[ "$line" =~ "$name" ]]
>
> To test whether one string contains another, use case:
>
> case $line in
> *"$name"*) # Do whatever
> ;;
> *) ;; # Do something else (or nothing)
> esac
>
> > then
> > echo $line
> > result=${line#'Bus '}
> > busnumber=${result%' Device'*}
> > result=${result#*'Device '}
>
> You don't need the single quotes.
>
> > devicenumber=${result%': ID'*}
> > echo $busnumber
> > echo $devicenumber
> > result="sudo fxload -I /usr/local/share/usb/maudio/MidiSport2x2.ihx -D /dev/bus/usb/"$busnumber"/"$devicenumber
> > echo $result
> > exec $result
> > fi
> > done
> > echo

The whole thing was rather cobbled together from looking up bits all
over the net (cos I don't have much idea what I'm doing). Most of the
stuff I found didn't really explain how things work so I had to keep
chopping and changing until it seemed to hang together. I wouldn't be
at all surprised to find that extracting the bus and device numbers
could be done more neatly. It certainly looks messy to me.

However, I'm a musician first and a programmer last, so once I get
things in a usable state it's hard for me to maintain the impetus to
improve things!

--
Will J G
From: Chris Davies on 16 Mar 2010 10:11
Folderol <folderol(a)ukfsn.org> wrote:
> The script below works perfectly in bash, but if I try to run it on a
> system with dash I get the following error:
> Start_Midisport.sh: 21: [[: not found

Chris Davies <chris-usenet(a)roaima.co.uk> asked:
> How do you run it (the exact command, please)?

Folderol replied:
> sh Start_Midisport.sh
> bash Start_Midisport.sh
> dash Start_Midisport.sh

Here you're using three potentially different shells, of which at least
one doesn't understand the [[ ... ]] syntax. All three invocations ignore
the #! instruction on the first line of your script.

The obvious fix is to make the script executable and treat it as such:

./Start_Midisport.sh

If you only have dash on your target device there's no point using bash
constructs and expecting them to work. Instead, you need to make the
script a dash script, and replace the [[ ... ]] construct with something
that works within dash.

Chris
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