diff --git a/contrib/bash_completion b/contrib/bash_completion
--- a/contrib/bash_completion
+++ b/contrib/bash_completion
@@ -1,22 +1,53 @@
 shopt -s extglob
 
+_hg_command_list()
+{
+    hg --debug help 2>/dev/null | \
+	awk 'function command_line(line) {
+		 gsub(/,/, "", line)
+		 gsub(/:.*/, "", line)
+		 split(line, aliases)
+		 command = aliases[1]
+		 delete aliases[1]
+		 print command
+		 for (i in aliases)
+		     if (index(command, aliases[i]) != 1)
+			 print aliases[i]
+	     }
+	     /^list of commands:/ {commands=1}
+	     commands && /^ debug/ {a[i++] = $0; next;}
+	     commands && /^ [^ ]/ {command_line($0)}
+	     /^global options:/ {exit 0}
+	     END {for (i in a) command_line(a[i])}'
+
+}
+
+_hg_option_list()
+{
+    hg -v help $1 2> /dev/null | \
+        awk '/^ *-/ {
+		 for (i = 1; i <= NF; i ++) {
+		    if (index($i, "-") != 1)
+			 break;
+		    print $i;
+		 }
+	     }'
+}
+
+
 _hg_commands()
 {
     local all commands result
 
-    all=($(hg --debug help | sed -e '1,/^list of commands:/d' \
-				 -e '/^global options:/,$d' \
-				 -e '/^ [^ ]/!d; s/^ //; s/[,:]//g;'))
-
-    commands="${all[*]##debug*}"
+    all=$(_hg_command_list)
+    commands=${all%%$'\n'debug*}
     result=$(compgen -W "$commands" -- "$cur")
 
     # hide debug commands from users, but complete them if
     # there is no other possible command
     if [ "$result" = "" ]; then
 	local debug
-	debug=(${all[*]##!(debug*)})
-	debug="${debug[*]/g/debug}"
+	debug=debug${all#*$'\n'debug}
 	result=$(compgen -W "$debug" -- "$cur")
     fi
 
@@ -90,8 +121,7 @@ shopt -s extglob
     done
 
     if [[ "$cur" == -* ]]; then
-	# this assumes that there are no commands with spaces in the name
-	opts=$(hg -v help $cmd | sed -e '/^ *-/!d; s/ [^- ].*//')
+	opts=$(_hg_option_list $cmd)
 
 	COMPREPLY=( ${COMPREPLY[@]:-} $(compgen -W "$opts" -- "$cur") )
 	return