When running a critical component of a system, it is important to know if that component exits. Furthermore, if the exit is unintended, maintaining a log of the output and error streams for that component can aid in failure analysis.
The daqstart component provides the ability to run an arbitrary executable (or script), capturing the error and or output to a timestamped log and informing you if the executable or script exits. The daqstart reference page describes the detailed use of the daqstart program.
Output monitoring by daqstart uses the concept of sinks. While the current implementation only supports file sinks, future implementations may provide other types of sinks such as pipes or interfaces to the unix system log facility, or even database logs.
Output sinks are specified using the form: type:destination where type defines the sink type (e.g. file), and the destination is sink type specific (e.g. for a file sink the destination is the name of the file that will be the sink).
Now a simple example:
Example 18-1. Logging errors and informing on exit
daqstart --error=file:/user/fox/logs/critical.log --notify \
mycriticalprogram --anoption=avalue argument
The logfile will be /user/fox/logs/critical.log. If that file exists new data will be appended to the log. Once a command argument that is not recognized by the daqstart program appears on the command line, the remainder of the line is considered to be the application that will be logged.