View Issue Details
| ID | Project | Category | View Status | Date Submitted | Last Update |
|---|---|---|---|---|---|
| 0001206 | 1003.1(2016/18)/Issue7+TC2 | Shell and Utilities | public | 2018-09-04 12:02 | 2019-04-04 15:15 |
| Reporter | kre | Assigned To | |||
| Priority | normal | Severity | Editorial | Type | Error |
| Status | Closed | Resolution | Rejected | ||
| Name | Robert Elz | ||||
| Organization | |||||
| User Reference | |||||
| Section | XCU 4 -- echo | ||||
| Page Number | 2675-6 | ||||
| Line Number | 87183, 87186, 87204, 87206 | ||||
| Interp Status | --- | ||||
| Final Accepted Text | |||||
| Summary | 0001206: The echo that supports -n is Bell Labs Unix echo, not "BSD echo" | ||||
| Description | The description of echo(1) in XCU Chapter 4, refers to the two common variants as "The historic System V echo" (line 87183) and "The BSD echo" (line 87186) (and both other places). The latter is factually incorrect, the former really is as well. That is, to the best of my recollection (and verification) BSD did absolutely nothing to echo, until attempts to make versions which could reconcile with the "other one" - echo (it appears) originated in 3rd edition Bell Labs Unix (without the -n flag, or any escape sequences, it was trivially simple). The -n option appeared in 7th edition Bell Labs Unix (and 32V). The first appearance of the version that allows \ sequences appears to have been from USL's PWB (version 1) (though it allowed just \\ \n \c and \0nnn .. though the latter formed 1 char from an unlimited number of octal digits after the \0). System III added \b \f \r \t and \v, and limited the number of octal digits after \0 to 3. Since PWB came between 6th and 7th edition unix, it is impossible (for me anyway) to determine which modification happened first (\c or -n). The current text in the standard makes it appear that the original is the one with the escapes the "historic" version (line 87183), and that, by implication, BSD changed it to make the "BSD version". That should be corrected. | ||||
| Desired Action | Change line 87183-4 to say The version of echo, originating from the USL PWB version of UNIX and distributed widely as part of System V, and the requirements on XSI implementations in this volume of POSIX.1-2008, are equivalent to: Change line 87186 to say The version of echo from Bell Labs UNIX, as enhanced in the 7th edition, and included with BSD distributions is equivalent to: If desired, one could add a 3rd variant: The original historic version of echo from original Bell Labs UNIX, from the 3rd to 6th editions, is equivalent to: printf "%s\n" "$*" (If there is any issue with using the TM "UNIX", amend as needed.) With those changes (not necessarily the reference to old Bell Labs versions) it should be OK to leave lines 87204 and 87206 unchanged. | ||||
| Tags | No tags attached. | ||||
| related to | 0001222 | Closed | "echo" specification doesn't reflect current implementations (missing -e, -E and - handling) |
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You are partially right. -n indeed first appeared in UNIX V7, but it has been removed with SVSV while introducing the backslash escapes. BSD on the other side took the UNIX V7 source and kept it for a long time. This may be the reason, why AT&T calls -n a "BSD feature". |
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This was discussed during the 2019-04-01 and 2019-04-04 conference calls... Although factually correct at this point, the discussions at the time the standard was being written were based on the then current UNIX System V echo and the BSD4.x echo. The rationale is consistent with those two versions of echo (no matter what either of them used as a basis for the way their code behaved). Trying to change the historical references at this point would do injustice to the discussions that were held at the time the standard was created. |
| Date Modified | Username | Field | Change |
|---|---|---|---|
| 2018-09-04 12:02 | kre | New Issue | |
| 2018-09-04 12:02 | kre | Name | => Robert Elz |
| 2018-09-04 12:02 | kre | Section | => XCU 4 -- echo |
| 2018-09-04 12:02 | kre | Page Number | => 2675-6 |
| 2018-09-04 12:02 | kre | Line Number | => 87183, 87186, 87204, 87206 |
| 2018-09-04 13:59 | joerg | Note Added: 0004101 | |
| 2019-04-01 16:33 | nick | Relationship added | related to 0001222 |
| 2019-04-04 15:15 | Don Cragun | Note Added: 0004352 | |
| 2019-04-04 15:15 | Don Cragun | Interp Status | => --- |
| 2019-04-04 15:15 | Don Cragun | Status | New => Closed |
| 2019-04-04 15:15 | Don Cragun | Resolution | Open => Rejected |
| 2019-04-04 16:53 | Don Cragun | Note Edited: 0004352 |
