SOLVED - WAS Re: [gentoo-user] Using date/time variables in cronjobs?

[Tanstaafl]

Just closing out this thread...

Thanks to your and Neill and others' help, I've settled on this for my 
nightly job, that also deletes the oldest hourly's and daily over a 
certain number to keep:

#!/bin/bash
BACKUP_DIR="/my/backups/app/sql/nightly"
BACKUP_DIR_hourly="/my/backups/app/sql/hourly"
PGUSER="SuperUser"
PG_my_app=`date '+%Y-%m-%d_%H:%M-app'`
/usr/bin/pg_dumpall -U $PGUSER -o -f $BACKUP_DIR/$PG_my_app-sql.gz
rm -f $(ls -1t $BACKUP_DIR/* | tail -n +91)
rm -f $(ls -1t $BACKUP_DIR_hourly/* | tail -n +36)

I'd like to learn how to do proper error detection using if/fi 
branching, but that will be a lesson for another day. I'll be monitoring 
these on a daily basis, so will hopefully catch any real problems before 
they cause any real problems.

Thanks again to all who helped me get these functional.


On 2013-05-05 11:25 PM, Pandu Poluan <pandu@××××××.info> wrote:
> In bash, underscores can be part of a variable name.
>
> $PGdd_$PGtt involves two variables: $PGdd_ (note the trailing
> underscore) and $PGtt
>
> You should write it like this:
>
> ${PGdd}_$PGtt
>
> The { } syntax is bash's way to indicate what exactly constitutes a
> variable name. IOW, the above construct has three parts: the variable
> $PGdd, an underscore, and the variable $PGtt
>
> Whenever you want to 'run' a variable name (i.e., combine it with other
> characters without specifying a whitespace), you should always use
> braces { } around the variable name.
>
> That said, since you're no longer creating a directory structure, why
> don't you just output everything using a single 'date' command? E.g. :
>
> date +'mypg-%Y-%m-%d_%H:%M'
>