[mythtv-users] Ways to Query Database From sh Script?
mkh01 at earthlink.net
Mon Feb 16 01:59:36 UTC 2009
On Sun, Feb 15, 2009 at 03:51:47PM -0800, Drew Tomlinson wrote:
> I'm working on my first UserJob script. In this script, I want to test
> if a recording has a cutlist before processing. I've Googled and the
> way found to query the database from /bin/sh goes like this:
> CUTLIST=`cat << EOF | mysql -u mythtv -pmythtv mythconverg
> basename = '$FILENAME';
> Using the above, $CUTLIST will be set to either "cutlist 1" or "cutlist
> 0" depending upon whether a cutlist exists. (I suppose piping to awk
> would remove "cutlist"). Is this the only way to query from /bin/sh?
> Is there a more practical way?
While this is the proper general approach for running DB queries from a
shell script, this specific example is unnecessarily ugly and
1. You don't need cat. It does nothing except feed a here document in to
mysql, so you might as well just use "mysql ... <<EOF" instead.
2. You don't need a here document anyway because that query is a
single-line statement so you could just echo it in to mysql.
3. But you don't need to echo it either because the man page for "mysql"
should mention the "-e" option that lets you pass a statement to be
executed on the command line.
4. While you are reading that man page to gain enlightenment you should
take note of options like "-N" and "-s" that reduce the output so you
won't get the column header in your variable.
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