Shell programmerings artikel

[Mads Bondo Dydensborg <sslug@sslug>]

Hejsa alle.

På 
http://linux.com/development/newsitem.phtml?sid=64&aid=10910

er der en ret uinteressant artikel om shell scripts/programmering. 

Til gengæld er der nogen _fede_ links i bunden, til folk der _virkeligt_
ved hvad de snakker om. F.eks. fra den om csh considered harmfull:

Et lille highlight
-----------------------------------
Consider the pipeline:

    A | B | C

You want to know the status of C, well, that's easy: it's in $?, or
$status in csh.  But if you want it from A, you're out of luck -- if
you're in the csh, that is.  In the Bourne shell, you can get it, although
doing so is a bit tricky.  Here's something I had to do where I ran dd's
stderr into a grep -v pipe to get rid of the records in/out noise, but had
to return the dd's exit status, not the grep's:

    device=/dev/rmt8
    dd_noise='^[0-9]+\+[0-9]+ records (in|out)$'
    exec 3>&1
    status=`((dd if=$device ibs=64k 2>&1 1>&3 3>&- 4>&-; echo $? >&4) |
                egrep -v "$dd_noise" 1>&2 3>&- 4>&-) 4>&1`
    exit $status;
------------------------

_DET_ er smukt. Kan næsten få en voksen mand til at tude... :-)

Check de links ud. Fede for shell'en.

Mads

-- 
Mads Bondo Dydensborg.                               sslug@sslug
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