234 lines
4.8 KiB
Plaintext
234 lines
4.8 KiB
Plaintext
.TH QER 8
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.SH NAME
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qer, runq \- queue management for spooled files
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.SH SYNOPSIS
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.B qer
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[
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.B -q
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.I subdir
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]
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[
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.B -f
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.I file
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]
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.I root tag reply args
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.br
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.B runq
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[
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.B -adsER
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]
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[
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.B -f
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.I file
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]
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[
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.B -q
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.I subdir
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]
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[
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.B -l
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.I load
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]
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[
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.B -t
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.I time
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]
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[
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.B -r
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.I nfiles
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]
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[
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.B -n
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.I nprocs
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]
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.I root cmd
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.SH DESCRIPTION
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.I Qer
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creates a control and a data file in a queue directory.
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The control file contents consist of the
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.IR tag ,
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.IR reply ,
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and
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.I args
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separated by spaces.
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The data file contains the standard input to
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.IR qer .
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The files are created in the directory
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.IR root / subdir ,
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where
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.I subdir
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is the argument to
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.B -q
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if present, else the contents of
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.BR /dev/user .
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The names of the control and data files differ only
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in the first character which is `C' and `D' respectively.
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.IR Mktemp (2)
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is used to create the actual names of the control and
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data file.
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.P
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Some commands, such as
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.I fax
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(see
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.IR telco (4)),
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must queue more files than just the data file.
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Each
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.I file
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following a
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.B \-f
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flag is copied into the queue directory. The names
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of the copies differ from the name of the data file
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only in the first character. The first one is
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starts with 'F', the second 'G', etc.
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.P
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.I Runq
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processes the files queued by
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.IR qer .
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Without the
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.B -a
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option,
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.I runq
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processes all requests in the directory
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.IR root / subdir ,
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where
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.I subdir
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is the argument to
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.B -q
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if present, else the contents of
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.BR /dev/user .
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With the
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.B -a
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it processes all requests.
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Each request is processed by executing the command
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.I cmd
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with the contents of the control file as its arguments,
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the contents of the data file as its standard input, and
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standard error appended to the error file
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.BR E.XXXXXX .
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.P
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The action taken by
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.I runq
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depends on the return status of
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.IR cmd .
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If
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.I cmd
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returns a null status, the processing is assumed successful and the
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control, data, and error files are removed.
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If
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.I cmd
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returns an error status containing the word
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.LR Retry ,
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the files are left to be reprocessed at a later time.
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For any other status, an error message is mailed
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to the requester and the files are removed.
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.I Runq
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uses the
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.I reply
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field in the control file as
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a mail address to which to send an error notification.
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The notification contains the contents of the control
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file to identify the failed request.
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.P
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To avoid reprocessing files too often, the following algorithm is used:
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a data file younger than one hour will not be processed if its
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error file exists and was last modified within the preceding 10 minutes.
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A data file older than one hour will not be processed if its error
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file exists and was last modified within the preceding hour.
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The
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.B -E
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flag causes all files to be reprocessed regardless of
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the file times.
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.P
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The
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.B -R
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flag instructs
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.I runq
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never to give up on a failed queue job, instead leaving
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it in the queue to be retried.
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.P
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The
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.B -d
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option causes debugging output on standard error
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describing the progress through the queues.
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.P
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The
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.B -t
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flags specifies the number of hours
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that retries will continue after a send
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failure. The default is 48 hours.
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.P
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The
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.BR -r
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flag limits the number of files that are processed in a single pass of a queue.
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.I Runq
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accumulates the entire directory containing a queue before processing any
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files. When a queue contains many files and the system does not
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have enough memory,
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.I runq
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exits without making progress. This flag forces
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.I runq
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to process the directory in chunks, allowing the queue to
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be drained incrementally. It is most useful in combination with the
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.I -q
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flag.
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.P
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The
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.BR -s ,
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.BR -n ,
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and
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.B -l
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flags are only meaningful with the
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.B -a
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flag. They control amount of parallelism that
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is used when sweeping all of the queues. The argument following the
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.B -n
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flag specifies the number of queues that are swept
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in parallel; the default is 50. The argument following the
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.B -l
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flag specifies the total number of queues that are being swept.
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By default, there is no limit. The number of active sweeps
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is cumulative over all active executions of
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.IR runq .
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The
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.B -s
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flag forces each queue directory to be processed by exactly
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one instance of
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.IR runq .
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This is useful on systems that connect to slow
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external systems and prevents all the queue sweeps from
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piling up trying to process a few slow systems.
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.PP
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.I Runq
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is often called from
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.IR cron (8)
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by an entry such as
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.IP
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.EX
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0,10,20,30,40,50 * * * * kremvax
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runq -a /mail/queue /mail/lib/remotemail
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.EE
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.LP
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The entry must be a single line; it is folded here only so it fits on the page.
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.SH FILES
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.TF \fIroot\fP/\fIuser\fP/[F-Z].XXXXXX
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.TP
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.B \fIroot\fP/\fIuser\fP
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queue directory for
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.I user
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.TP
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.B \fIroot\fP/\fIuser\fP/D.XXXXXX
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data file
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.TP
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.B \fIroot\fP/\fIuser\fP/C.XXXXXX
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control file
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.TP
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.B \fIroot\fP/\fIuser\fP/E.XXXXXX
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error file
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.TP
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.B \fIroot\fP/\fIuser\fP/[F-Z].XXXXXX
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secondary data files
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.SH SOURCE
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.B /sys/src/cmd/upas/q
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.SH "SEE ALSO"
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.IR mail (1)
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