diff --git a/bin/pt-ioprofile b/bin/pt-ioprofile
index c9bb3c99..6a2609ab 100755
--- a/bin/pt-ioprofile
+++ b/bin/pt-ioprofile
@@ -443,9 +443,13 @@ rm_tmpdir() {
 
 # ###########################################################################
 # alt_cmds package
+# This package is a copy without comments from the original.  The original
+# with comments and its test file can be found in the Bazaar repository at,
+#   lib/bash/alt_cmds.sh
+#   t/lib/bash/alt_cmds.sh
+# See https://launchpad.net/percona-toolkit for more information.
 # ###########################################################################
 
-# seq N, return 1, ..., 5
 _seq() {
    local i="$1"
    awk "BEGIN { for(i=1; i<=$i; i++) print i; }"
@@ -466,8 +470,6 @@ _lsof() {
 }
 
 _which() {
-   # which on CentOS is aliased to a cmd that prints extra stuff.
-   # Also, if the cmd isn't found, a msg is printed to stderr.
    [ -x /usr/bin/which ] && /usr/bin/which "$1" 2>/dev/null | awk '{print $1}'
 }
 
diff --git a/bin/pt-stalk b/bin/pt-stalk
index 5d8fa048..53a7b684 100755
--- a/bin/pt-stalk
+++ b/bin/pt-stalk
@@ -631,7 +631,7 @@ collect() {
    local d="$1"  # directory to save results in
    local p="$2"  # prefix for each result file
 
-   local mysqld_pid=$(_pidof mysqld | head -n1)
+   local mysqld_pid=$(_pidof mysqld | awk '{print $1; exit;}')
 
    if [ "$CMD_PMAP" -a "$mysqld_pid" ]; then
       if $CMD_PMAP --help 2>&1 | grep -- -x >/dev/null 2>&1 ; then
@@ -783,7 +783,7 @@ collect() {
       $CMD_OPCONTROL --stop
       $CMD_OPCONTROL --dump
 
-      local oprofiled_pid=$(_pidof oprofiled)
+      local oprofiled_pid=$(_pidof oprofiled | awk '{print $1; exit;}')
       if [ "$oprofiled_pid" ]; then
          kill $oprofiled_pid
       else
diff --git a/lib/bash/collect.sh b/lib/bash/collect.sh
index ee1b5965..9cba7cef 100644
--- a/lib/bash/collect.sh
+++ b/lib/bash/collect.sh
@@ -49,7 +49,7 @@ collect() {
    local p="$2"  # prefix for each result file
 
    # Get pidof mysqld.
-   local mysqld_pid=$(_pidof mysqld | head -n1)
+   local mysqld_pid=$(_pidof mysqld | awk '{print $1; exit;}')
 
    # Get memory allocation info before anything else.
    if [ "$CMD_PMAP" -a "$mysqld_pid" ]; then
@@ -236,7 +236,7 @@ collect() {
       $CMD_OPCONTROL --stop
       $CMD_OPCONTROL --dump
 
-      local oprofiled_pid=$(_pidof oprofiled)
+      local oprofiled_pid=$(_pidof oprofiled | awk '{print $1; exit;}')
       if [ "$oprofiled_pid" ]; then
          kill $oprofiled_pid
       else