Bug 175907

Summary:	"tail +10" no longer works
Product:	[Fedora] Fedora	Reporter:	John Ellson <john.ellson>
Component:	coreutils	Assignee:	Tim Waugh <twaugh>
Status:	CLOSED NOTABUG	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	rawhide	CC:	davej
Target Milestone:	---	Keywords:	Reopened
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2007-02-06 09:45:21 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description John Ellson 2005-12-16 04:09:20 UTC

Description of problem:
"tail +10"  no longer works

Version-Release number of selected component (if applicable):
coreutils-5.93-4.1

How reproducible:
100%

Steps to Reproduce:
1.tail +10 somefile
2.
3.
  
Actual results:
tail: cannot open `+10' for reading: No such file or directory.


Expected results:
all the lines in the file except the first 10

Additional info:
Even if someone has taken a dislike to this option, it is still required
for backward compatibility as many scripts use it.
Also, the option is still described in the man page.

Comment 1 Dave Jones 2005-12-16 04:15:43 UTC

sort is similarly broken.

Comment 2 Tim Waugh 2005-12-16 09:50:03 UTC

Here is what the tail man page actually says:

       -n, --lines=N
              output the last N lines, instead of the last 10
[...]
       If the first character of N (the number of bytes or lines)  is  a  â+â,
       print  beginning  with the Nth item from the start of each file, other-
       wise, print the last N items in the file.  N may have a multiplier suf-
       fix: b 512, k 1024, m 1024*1024.

So for tail, use 'tail -n +10'.  If you really must use the old 'tail +10'
syntax (which is no longer described in the man page), set
_POSIX2_VERSION=199209 in the environment.

For more information, see:

info coreutils "Standards Conformance"


*** This bug has been marked as a duplicate of 174624 ***

Comment 3 John Ellson 2005-12-16 11:19:18 UTC

Here is what the tail man page actually says:

      -n, --lines=N
              output the last N lines, instead of the last 10
...
       If the first character of N (the number of bytes or lines)  is  a  â+â,
       print  beginning  with the Nth item from the start of each file, other-
       wise, print the last N items in the file.  N may have a multiplier suf-
       fix: b 512, k 1024, m 1024*1024.


$ rpm -qf /usr/share/man/man1/tail.1.gz
coreutils-5.93-4.1

Not only that, but "tail --help" says the thing.


The problem came up because Sun's JAI installation script fails.   Do you
really want to break hundreds of scripts by other vendors?  Why?

Please make _POSIX2_VERSION=199209 the default.

Comment 4 John Ellson 2005-12-16 11:26:40 UTC

OK, I get it, if you read the man page like a lawyer, and without previous
knowledge, it doesn't actually say tail with an unadorned +N is permitted.

Given the previous 30year usage of tail I think it might be a little clearer
about the change.   It should also properly document the environment variable
setting
for bringing the previous behavior back.

Comment 5 John Ellson 2005-12-16 11:34:14 UTC

The man page also doesn't describe -N, but "tail -30" works.

Comment 6 Red Hat Bugzilla 2007-02-05 19:05:05 UTC

REOPENED status has been deprecated. ASSIGNED with keyword of Reopened is preferred.

Comment 7 Tim Waugh 2007-02-06 09:45:21 UTC

The man page deliberately omits the description of this non-POSIX option form.