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Redirecting STDOUT

Theme: Configure
Who Is It For? System Administrator

What is it?​

Reference for redirecting STDOUT output from Unix Agent jobs, including use of the captureSTDOUT script and behavior differences based on the path_to_su parameter.

Redirect STDOUT when:

  • The path_to_su parameter is set to No and a job must write its output to a specific file, because in this configuration the agent does not correctly interpret a redirection character (>) in a Start Image received from the Enterprise Manager.

  • A job's output would otherwise accumulate in the LSAM_output_<SAM_socket> file in the agent root directory, making it difficult to identify or archive output for individual jobs.

  • Using the captureSTDOUT script or a wrapper script provides a consistent, maintainable approach to output handling that works for any job without modifying the individual scripts themselves.

How to implement it​

To redirect STDOUT for Unix Agent jobs, complete the following steps:

  • Review the path_to_su setting — if path_to_su is set to Yes, redirection in the Start Image works directly; if it is set to No, use the captureSTDOUT script or embed redirection logic inside the job script.
  • Use the captureSTDOUT script — pass the output file path and the script path as arguments so the agent routes job output to the specified file rather than the LSAM_output_<SAM_socket> file in the agent root directory.

Exception handling​

Job output is written to LSAM_output_<SAM_socket> instead of the specified file — The path_to_su parameter is set to No and the redirection character (>) was placed in the Start Image rather than inside a script or handled by captureSTDOUT. — Either embed the output redirection within the job script itself, or set the Start Image to invoke captureSTDOUT with the output file path and script path as arguments as described in the Syntax section.

captureSTDOUT script fails or produces errors for the current shell — The script template is written for the Korn shell; running it under a different shell without modification causes syntax errors or unexpected behavior. — Edit captureSTDOUT in <LSAM root path>/bin/ to match the syntax of the shell in use on the system before referencing it in job definitions.

Output file is not created at the specified path — The directory path supplied as the first argument to captureSTDOUT does not exist, or the agent's user does not have write permission to that directory. — Verify that the target directory exists and that the user identity under which the job runs has write access to it.

If the parameter path_to_su is set to Yes, redirecting STDOUT in the start image received from the Enterprise Manager will work fine.

If the parameter path_to_su is set to No, redirecting STDOUT must take place within a script. Because of its design, the LSAM does not correctly interpret a redirection character (>) in a Start Image received from the Enterprise Manager. Each script must contain the code to redirect STDOUT, or a wrapper script can receive each script and handle the redirection. If the output is not redirected, it will be sent to the LSAM_output file, LSAM_output_<SAM_socket> in the agent root directory.

SMA Technologies provides a generic script captureSTDOUT that redirects STDOUT for any script. The captureSTDOUT script resides in the <LSAM root path>/bin directory. This script is a working template, and is open to modification by a system programmer to contain more detailed information. The template is for use with the Korn shell; therefore, be sure to adjust the script according to the shell in use.

For information on analyzing standard out to determine exit conditions, refer to [sma_ppscript]../../operations/utilities/sma-ppscript).

Syntax​

<path>/captureSTDOUT <path to output file> <path to script>

The <path> points to the LSAM "bin/" directory (e.g., "/usr/local/lsam/bin").

Example

An example UNIX job has the following characteristics:

The job to run has the following path: /usr/local/payroll/timecalc The standard output from the job goes to the following file: /usr/local/payroll/finished/timecalc.datetime. Assuming the captureSTDOUT file is in the LSAM /bin directory, the Start Image and Parameters on the UNIX Details screen (in the Enterprise Manager's Job Master) for the above job would contain the following:

Start Image: /usr/local/lsam/bin/captureSTDOUT

Parameters: /usr/local/payroll/finished/timecalc.datetime/usr/local/payroll/timecalc

For more information, refer to UNIX Job Details in the Concepts online help.