QMSG(1P)

PROLOG
This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (consult the corresponding Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.

NAME
qmsg — send message to batch jobs

SYNOPSIS

qmsg [-EO] message_string job_identifier...

DESCRIPTION
To send a message to a batch job is to request that a server write a message string into one or more output files of the batch job. A message is sent to a batch job by a request to the batch server that manages the batch job. The qmsg utility is a user-accessible batch client that requests the sending of messages to one or more batch jobs.

The qmsg utility shall write messages into the files of batch jobs by sending a Job Message Request to the batch server that manages the batch job. The qmsg utility shall not directly write the message into the files of the batch job.

The qmsg utility shall send a Job Message Request for those batch jobs, and only those batch jobs, for which a batch job_identifier is presented to the utility.

The qmsg utility shall send Job Message Requests for batch jobs in the order in which their batch job_identifiers are presented to the utility.

If the qmsg utility fails to process any batch job_identifier successfully, the utility shall proceed to process the remaining batch job_identifiers, if any.

The qmsg utility shall not exit before a Job Message Request has been sent to the server that manages the batch job that corresponds to each successfully processed batch job_identifier.

OPTIONS
The qmsg utility shall conform to the Base Definitions volume of POSIX.1-2017, Section 12.2, Utility Syntax Guidelines.

The following options shall be supported by the implementation:

-E  Specify that the message is written to the standard error of each batch job.

    The qmsg utility shall write the message into the standard error of the batch job.

-O  Specify that the message is written to the standard output of each batch job.

    The qmsg utility shall write the message into the standard output of the batch job.

If neither the -O nor the -E option is presented to the qmsg utility, the utility shall write the message into an implementation-defined file. The conformance document for the implementation shall describe the name and location of the implementation-defined file. If both the -O and the -E options are presented to the qmsg utility, then the utility shall write the messages to both standard output and standard error.

OPERANDS
The qmsg utility shall accept a minimum of two operands, message_string and one or more batch job_identifiers.

The message_string operand shall be the string to be written to one or more output files of the batch job followed by a <newline>. If the string contains <blank> characters, then the application shall ensure that the string is quoted. The message_string shall be encoded in the portable character set (see the Base Definitions volume of POSIX.1-2017, Section 6.1, Portable Character Set).

All remaining operands are batch job_identifiers that conform to the syntax for a batch job_identifier (see Section 3.3.1, Batch Job Identifier).

STDIN
Not used.

INPUT FILES
None.

ENVIRONMENT VARIABLES
The following environment variables shall affect the execution of qmsg:

LANG
    Provide a default value for the internationalization variables that are unset or null. (See the Base Definitions volume of POSIX.1-2017, Section 8.2, Internationalization Variables the precedence of internationalization variables used to determine the values of locale categories.)

LC_ALL
    If set to a non-empty string value, override the values of all the other internationalization variables.

LC_CTYPE
    Determine the locale for the interpretation of sequences of bytes of text data as characters (for example, single-byte as opposed to multi-byte characters in arguments).

LC_MESSAGES
    Determine the locale that should be used to affect the format and contents of diagnostic messages written to standard error.

LOGNAME
    Determine the login name of the user.

ASYNCHRONOUS EVENTS
Default.

STDOUT
None.

STDERR
The standard error shall be used only for diagnostic messages.

OUTPUT FILES
None.

EXTENDED DESCRIPTION
None.

EXIT STATUS
The following exit values shall be returned:

0   Successful completion.

>0  An error occurred.

CONSEQUENCES OF ERRORS
In addition to the default behavior, the qmsg utility shall not be required to write a diagnostic message to standard error when the error reply received from a batch server indicates that the batch job_identifier does not exist on the server. Whether or not the qmsg utility waits to output the diagnostic message while attempting to locate the job on other servers is implementation-defined.

The following sections are informative.

APPLICATION USAGE
None.

EXAMPLES
None.

RATIONALE
The qmsg utility allows users to write messages into the output files of running jobs. Users, including operators and administrators, have a number of occasions when they want to place messages in the output files of a batch job. For example, if a disk that is being used by a batch job is showing errors, the operator might note this in the standard error stream of the batch job.

The options of the qmsg utility provide users with the means of placing the message in the output stream of their choice. The default output stream for the message—if the user does not designate an output stream—is implementation-defined, since many implementations will provide, as an extension to this volume of POSIX.1-2017, a log file that shows the history of utility execution.

If users wish to send a message to a set of jobs that meet a selection criteria, the qselect utility can be used to acquire the appropriate list of job identifiers.

The -E option allows users to place the message in the standard error stream of the batch job.

The -O option allows users to place the message in the standard output stream of the batch job.

Historically, the qmsg utility is an existing practice in the offerings of one or more implementors of an NQS-derived batch system. The utility has been found to be useful enough that it deserves to be included in this volume of POSIX.1-2017.

FUTURE DIRECTIONS
The qmsg utility may be removed in a future version.

SEE ALSO
Chapter 3, Batch Environment Services, qselect

The Base Definitions volume of POSIX.1-2017, Section 6.1, Portable Character Set, Chapter 8, Environment Variables, Section 12.2, Utility Syntax Guidelines

COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1-2017, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 7, 2018 Edition, Copyright (C) 2018 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained online at http://www.opengroup.org/unix/online.html .

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