From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tom Rini Date: Thu, 6 Sep 2012 15:45:36 -0700 Subject: [U-Boot] [PATCH V2 4/4] cmd_part: add partition-related command In-Reply-To: <5048EF79.50703@wwwdotorg.org> References: <1346882624-12783-1-git-send-email-swarren@wwwdotorg.org> <1346882624-12783-4-git-send-email-swarren@wwwdotorg.org> <5047E59E.8060503@gmail.com> <50480CA2.2040606@wwwdotorg.org> <20120906171235.GA15624@bill-the-cat> <5048EF79.50703@wwwdotorg.org> Message-ID: <50492790.8080703@ti.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de On 09/06/2012 11:46 AM, Stephen Warren wrote: > On 09/06/2012 11:12 AM, Tom Rini wrote: >> On Wed, Sep 05, 2012 at 08:38:26PM -0600, Stephen Warren wrote: >>> On 09/05/2012 05:51 PM, Rob Herring wrote: >>>> On 09/05/2012 05:03 PM, Stephen Warren wrote: >>>>> From: Stephen Warren >>>>> >>>>> This implements the following: >>>>> >>>>> part uuid mmc 0:1 >>>>> -> print partition UUID >>>>> part uuid mmc 0:1 uuid >>>>> -> set environment variable to partition UUID >>>> >>>> What's the reason to not always both print out and set the uuid env var? >>>> >>>> Perhaps the env name should be partuuid or part_uuid as you could have >>>> uuid's for other purposes? >>> >>> The idea is that if you're running the command interactively, you won't >>> pass a variable name on the command-line, so the command will print out >>> the UUID for you to read. In this case, it's pointless to set any >>> environment variable. >>> >>> However, if you're writing a script, you want to capture the UUID into >>> an environment variable, and it's quite unlikely you want to litter >>> stdout with that content too. Hence, either-or, not both. >> >> Do other commands have a "I'm being scripted, probably, don't stdout" >> and "I'm being interactive, use stdout" distinction like this? IMHO, >> always printing out makes sense so you can "see" that your script is >> working as you expect. > > In general, as a script writer, yes you do have the ability to choose. > Typically, I'd write: > > part uuid .... > > vs. > > var=`part uuid ....` > > in order to control this. However, U-Boot's shell doesn't support > backticks. As a script writer, I certainly desire the ability to control > what commands spam to the console, and really don't think it's useful to > print the UUID from a script (does the user really care, and any script > developer can just echo it for debugging if they need it). > > I'm not aware of other U-Boot commands whose purpose it is to set > environment variables, so can't really compare. > > Still, if you're insistent on this point, I can change the code to > always print, and optionally write an environment variable. No, you make a good point. Thanks! -- Tom