View Issue Details
| ID | Project | Category | View Status | Date Submitted | Last Update |
|---|---|---|---|---|---|
| 0000962 | 1003.1(2013)/Issue7+TC1 | Shell and Utilities | public | 2015-06-20 20:42 | 2019-06-10 08:54 |
| Reporter | rhymoid | Assigned To | |||
| Priority | normal | Severity | Comment | Type | Clarification Requested |
| Status | Closed | Resolution | Accepted As Marked | ||
| Name | Stijn van Drongelen | ||||
| Organization | |||||
| User Reference | |||||
| Section | sort | ||||
| Page Number | 3211 | ||||
| Line Number | 107616-107618 | ||||
| Interp Status | Approved | ||||
| Final Accepted Text | see 0000962:0002764 | ||||
| Summary | 0000962: Should utilities continue when reading one of multiple files fails? | ||||
| Description | Consider the following sequence of commands: set +e rm -f aaaa echo something >xxxx echo c_mpletely >yyyy echo different >zzzz cat aaaa xxxx 2>/dev/null sed -e s/_/o/ aaaa yyyy 2>/dev/null sort aaaa zzzz 2>/dev/null On FreeBSD and Mac OS X, this sequence prints the following to standard output something completely To be specific: cat and sed continue their task when a specified file could not be opened, while sort terminates without output to stdout when any of the specified files could not be opened. From the description of cat in the POSIX specification, it seems that it is not defined whether the cat, sed, and sort utilities should terminate when an error occurred when processing a specified file. It would seem that the output of the sequence above may range from "" to "something\ncompletely\ndifferent\n" across POSIX implementations. | ||||
| Desired Action | Clarify the constraints, if any, on the behaviour of cat, sed, and sort when opening or reading one of their input files fails. | ||||
| Tags | tc2-2008 | ||||
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See XCU 1.4 Utility Description Defaults, under CONSEQUENCES OF ERRORS, where it says: The following shall apply to each utility, unless otherwise stated: * If the requested action cannot be performed on an operand representing a file, directory, user, process, and so on, the utility shall issue a diagnostic message to standard error and continue processing the next operand in sequence, but the final exit status shall be returned as non-zero. It appears that most, if not all, implementations of sort do not follow this general rule. We should add something to the sort page (either in OPERANDS or CONSEQUENCES OF ERRORS) to say that if sort encounters an error when opening or reading a file operand, it may exit without processing later operands. |
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Interpretation response ------------------------ The standard states that sort must carry on processing later operands after an error is encountered with an earlier operand, and conforming implementations must conform to this. However, concerns have been raised about this which are being referred to the sponsor. Rationale: ------------- Existing implementations of sort stop processing immediately after encountering an error when reading input files. Notes to the Editor (not part of this interpretation): ------------------------------------------------------- On page 3211 line 107618 (sort OPERANDS), append the following to the description of the file operand: If sort encounters an error when opening or reading a file operand, it may exit without writing any output to standard output or processing later operands. On page 3213 line 107687 (sort CONSEQUENCES OF ERRORS), change from: Default.to: The default requirements shall apply, except that if sort encounters an error when opening or reading a file operand, it may exit without writing any output to standard output or processing later operands. |
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Interpretation Proposed: 17 July 2015 |
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Interpretation approved: 7 Sep 2015 |
| Date Modified | Username | Field | Change |
|---|---|---|---|
| 2015-06-20 20:42 | rhymoid | New Issue | |
| 2015-06-20 20:42 | rhymoid | Name | => Stijn van Drongelen |
| 2015-06-20 20:42 | rhymoid | Section | => cat, sed, sort |
| 2015-06-20 20:42 | rhymoid | Page Number | => N/A |
| 2015-06-20 20:42 | rhymoid | Line Number | => N/A |
| 2015-06-22 08:41 | geoffclare | Note Added: 0002727 | |
| 2015-07-16 15:53 | rhansen | Section | cat, sed, sort => sort |
| 2015-07-16 15:53 | rhansen | Page Number | N/A => 3211 |
| 2015-07-16 15:53 | rhansen | Line Number | N/A => 107616-107618 |
| 2015-07-16 15:53 | rhansen | Interp Status | => --- |
| 2015-07-16 16:15 | rhansen | Note Added: 0002764 | |
| 2015-07-16 16:16 | rhansen | Interp Status | --- => Pending |
| 2015-07-16 16:16 | rhansen | Final Accepted Text | => see 0000962:0002764 |
| 2015-07-16 16:16 | rhansen | Status | New => Interpretation Required |
| 2015-07-16 16:16 | rhansen | Resolution | Open => Accepted As Marked |
| 2015-07-16 16:16 | rhansen | Tag Attached: tc2-2008 | |
| 2015-07-17 07:59 | ajosey | Interp Status | Pending => Proposed |
| 2015-07-17 07:59 | ajosey | Note Added: 0002769 | |
| 2015-09-07 11:32 | ajosey | Interp Status | Proposed => Approved |
| 2015-09-07 11:32 | ajosey | Note Added: 0002816 | |
| 2019-06-10 08:54 | agadmin | Status | Interpretation Required => Closed |
