Date: Thu, 16 Feb 2006 19:19:24 -0600 From: Dan Nelson <dnelson@allantgroup.com> To: Tim Daneliuk <tundra@tundraware.com> Cc: freebsd-questions@freebsd.org Subject: Re: /bin/sh Madness Message-ID: <20060217011923.GA87403@dan.emsphone.com> In-Reply-To: <43F50074.8060205@tundraware.com> References: <43F50074.8060205@tundraware.com>
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In the last episode (Feb 16), Tim Daneliuk said:
> Here is a shell function that behaves quite strangely:
>
> #!/bin/sh
> #####
> # Execute A Command, Noting Start/Stop Time, & Logging Output
> # Args:
> # $1 Command Name
> # $2 Log Directory
> # $3 Command String To Execute
> #####
>
> runupd()
> {
> log=$2/$1.log
> timestamp $log
> touch $2/.$1-begin && eval $3 2>&1 >> $log && touch $2/.$1-end &
> }
> # End of 'runupd()'
>
> So, you might do something like:
>
> runupd freespace /var/log/ "df -k"
>
> Now, for the weirdness. This function works fine in my script
> so long as one of two conditions is met:
>
> 1) I run it interactively from the command line (bash)
> OR
> 2) I run it from 'cron' AND $3 is *not* another script
>
> If I try to run it from 'cron' and point $3 to a script, everything gets
> run as planned, however, the ending timestamp (touch $2/.$1-end) never
> runs. That is, the initial time stamp (.$1-begin) and the command itself
> are executed, and output is properly written to the logfile,
> but the final timestamp never happens.
Could your $3 command be returning a nonzero exit code? You probably
want something more like
touch $2/.$1-begin && { eval $3 2>&1 >> $log ; touch $2/.$1-end } &
so your end timestamp always gets created whether or not $3 succeeds.
Also note that in your original script, you only backgrounded "touch
$2/.$1-end", which is probably not what you wanted.
--
Dan Nelson
dnelson@allantgroup.com
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