svn commit: r345005 - head/libexec/rc/rc.d

[Kurt Lidl]

Author: lidl
Date: Mon Mar 11 13:33:03 2019
New Revision: 345005
URL: https://svnweb.freebsd.org/changeset/base/345005

Log:
  Remove an unneeded 'tail -n 1' from a pipeline
  
  When piping to awk, it's almost always an anti-pattern to use 'grep'
  first.
  
  When not in a pipeline, sometimes it is faster to use tail, as awk
  must process all the lines in the input stream, and won't 'seek'.
  In a pipeline, both grep and awk must process all lines, so we might
  as well skip the extra process creation for tail and just use awk
  for all the processing.
  
  Reviewed by:	jilles
  MFC after:	2 weeks
  Differential Revision:	https://reviews.freebsd.org/D19441

Modified:
  head/libexec/rc/rc.d/growfs

Modified: head/libexec/rc/rc.d/growfs
==============================================================================
--- head/libexec/rc/rc.d/growfs	Mon Mar 11 10:42:09 2019	(r345004)
+++ head/libexec/rc/rc.d/growfs	Mon Mar 11 13:33:03 2019	(r345005)
@@ -57,7 +57,7 @@ growfs_start ()
 		;;
 	zfs)
 		pool=${FSDEV%%/*}
-		rootdev=$(zpool list -v $pool | tail -n 1 | awk '{ print $1 }')
+		rootdev=$(zpool list -v $pool | awk 'END { print $1 }')
 		;;
 	*)
 		echo "Don't know how to grow root filesystem type: $FSTYPE"