--- old/./get_source.sh	2014-06-26 11:59:05.087310272 -0700
+++ new/./get_source.sh	2014-06-26 11:59:04.995310268 -0700
@@ -25,6 +25,20 @@
 # questions.
 #
 
+to_stderr() {
+    echo "$@" >&2
+}
+
+error() {
+    to_stderr "ERROR: $1"
+    exit ${2:-126}
+}
+
+warning() {
+    to_stderr "WARNING: $1"
+}
+
+
 # Version check
 
 # required
@@ -37,32 +51,36 @@
 rqstminor=6
 rqstrev=3
 
+
 # installed
-hgwhere="`which hg 2> /dev/null | grep -v '^no hg in '`"
+hgwhere="`command -v hg`"
 if [ "x$hgwhere" = "x" ]; then
-  echo "ERROR: Could not locate Mercurial command" >&2
-  exit 126
+  error "Could not locate Mercurial command"
 fi
 
-hgversion="`hg --version 2> /dev/null | sed -n -e 's@^Mercurial Distributed SCM (version \(.*\))\$@\1@p'`"
+hgversion="`hg --version 2> /dev/null | sed -n -e 's@^Mercurial Distributed SCM (version \([^+]*\).*)\$@\1@p'`"
 if [ "x${hgversion}" = "x" ] ; then
-  echo "ERROR: Could not determine Mercurial version" >&2
-  exit 126
+  error "Could not determine Mercurial version of $hgwhere"
+fi
+
+hgmajor="`echo $hgversion | cut -f 1 -d . | xargs expr 0 + 2> /dev/null || echo -1`"
+hgminor="`echo $hgversion | cut -f 2 -d . | xargs expr 0 + 2> /dev/null || echo -1`"
+hgrev="`echo $hgversion.0 | cut -f 3 -d . | xargs expr 0 + 2> /dev/null || echo -1`" # rev is omitted for minor and major releases
+
+if [ $hgmajor -eq -1 -o $hgminor -eq -1 -o $hgrev -eq -1 ] ; then
+  error "Could not determine Mercurial version of $hgwhere from \"$hgversion\""
 fi
 
-hgmajor="`echo $hgversion | cut -f 1 -d .`"
-hgminor="`echo $hgversion | cut -f 2 -d .`"
-hgrev="`echo $hgversion.0 | cut -f 3 -d .`" # rev is omitted for minor and major releases
 
 # Require
 if [ $hgmajor -lt $reqdmajor -o \( $hgmajor -eq $reqdmajor -a $hgminor -lt $reqdminor \) -o \( $hgmajor -eq $reqdmajor -a $hgminor -eq $reqdminor -a $hgrev -lt $reqdrev \) ] ; then
-  echo "ERROR: Mercurial version $reqdmajor.$reqdminor.$reqdrev or later is required. $hgwhere is version $hgversion" >&2
-  exit 126
+  error "Mercurial version $reqdmajor.$reqdminor.$reqdrev or later is required. $hgwhere is version $hgversion"
 fi
 
+
 # Request
 if [ $hgmajor -lt $rqstmajor -o \( $hgmajor -eq $rqstmajor -a $hgminor -lt $rqstminor \) -o \( $hgmajor -eq $rqstmajor -a $hgminor -eq $rqstminor -a $hgrev -lt $rqstrev \) ] ; then
-  echo "WARNING: Mercurial version $rqstmajor.$rqstminor.$rqstrev or later is recommended. $hgwhere is version $hgversion" >&2
+  warning "Mercurial version $rqstmajor.$rqstminor.$rqstrev or later is recommended. $hgwhere is version $hgversion"
 fi
 
 # Get clones of all absent nested repositories (harmless if already exist)