Re: tail +N vs. tail -n N

[Paul Eggert]

Greg Jednaszewski <address@hidden> writes:

> tail: `+5' option is obsolete; use `-n 5' since this will be removed in 
> the future

This message is no longer present in coreutils CVS.  Now, "tail"
silently uses either the old meaning of +5 (as an option) or the new
meaning (as a file name), depending on whether you're in backward
compatibility mode.  So the issue of the incorrect diagnostic is moot.

> Second, there does not seem to be an equivalent option for tail +N. 

Actually there is.  You can use, for example, "tail -n +12".

> http://linux.org.mt/article/selfextract

Ramon, can you please change all instances of "tail +" to "tail -n +"
in that URL?  "tail +" is not portable to POSIX 1003.1-2001 hosts, and
some GNU/Linux installations work that way these days.  Here is a
patch.  (Admittedly "tail -n +12" will not work on old-fashioned
implementations like Solaris; if that's a concern to you, I can send a
more-complicated patch.)

--- selfextract.old     2005-07-05 16:20:33.000000000 -0700
+++ selfextract 2005-07-05 16:21:34.000000000 -0700
@@ -62,7 +62,7 @@ echo &quot;&quot;
 # take the archive portion of this file and pipe it to tar
 # the NUMERIC parameter in this command should be one more
 # than the number of lines in this header file
-<b>tail +12 $0</b> | <b>tar xz</b>
+<b>tail -n +12 $0</b> | <b>tar xz</b>
 
 exit 0
 </pre>
@@ -103,7 +103,7 @@ echo &quot;&quot;
 <b>SKIP=`awk &apos;/^__ARCHIVE_FOLLOWS__/ { print NR + 1; exit 0; }&apos; 
$0`</b>
 
 # take the archive portion of this file and pipe it to tar
-tail <b>+$SKIP</b> $0 | tar xz
+tail -n <b>+$SKIP</b> $0 | tar xz
 
 
 exit 0
@@ -143,7 +143,7 @@ echo &quot;&quot;
 SKIP=`awk &apos;/^__ARCHIVE_FOLLOWS__/ { print NR + 1; exit 0; }&apos; $0`
 
 # Take the TGZ portion of this file and pipe it to tar.
-tail +$SKIP $0 | tar xz <b>-C $WRKDIR</b>
+tail -n +$SKIP $0 | tar xz <b>-C $WRKDIR</b>
 
 # execute the installation script
 <b>
@@ -176,7 +176,7 @@ Some *nix systems might not have the GNU
 and <tt>gzip</tt> commands to be separated. In this case, the command to 
decompress
 and extract the archive could be done as follows:
 </p>
-<pre>tail +$SKIP $0 <b>| gzip -dc</b> | tar x -</pre>
+<pre>tail -n +$SKIP $0 <b>| gzip -dc</b> | tar x -</pre>
 <hr noshade="1" size="1" color="black" />
 <p>
 The self-installing archive removes the contents of the temporary directory