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[PATCH v5 3/5] grub-mkconfig hurd: Fix quadratic algorithm for sorting m

From: Mathieu Desnoyers
Subject: [PATCH v5 3/5] grub-mkconfig hurd: Fix quadratic algorithm for sorting menu items
Date: Thu, 9 Jun 2022 14:50:22 -0400

The current implementation of the 10_hurd script implements its menu
items sorting in bash with a quadratic algorithm, calling "sed", "sort",
"head", and "grep" to compare versions between individual lines, which
is annoyingly slow for kernel developers who can easily end up with
50-100 kernels in their boot partition.

This fix is ported from the 10_linux script, which has a similar
quadratic code pattern.

[ Note: this is untested. I would be grateful if anyone with a Hurd
  environment could test it before it is merged. ]

Signed-off-by: Mathieu Desnoyers <>
Cc: Samuel Thibault <>
Changes since v4:
- Combine sed -e '...' -e '...' into sed -e '...; ...'
 util/grub.d/ | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/util/grub.d/ b/util/grub.d/
index 2fafa4e59..4294bbe4c 100644
--- a/util/grub.d/
+++ b/util/grub.d/
@@ -197,11 +197,17 @@ title_correction_code=
 # Extra indentation to add to menu entries in a submenu. We're not in a submenu
 # yet, so it's empty. In a submenu it will be equal to '\t' (one tab).
-while [ "x$kernels" != "x" ] ; do
-  kernel=`version_find_latest $kernels`
+# Perform a reverse version sort on the entire kernels list.
+# Temporarily replace the '.old' suffix by ' 1' and append ' 2' for all
+# other files to order the '.old' files after their non-old counterpart
+# in reverse-sorted order.
+reverse_sorted_kernels=$(echo ${kernels} | tr ' ' '\n' | sed -e 's/\.old$/ 1/; 
/ 1$/! s/$/ 2/' | version_sort -r | sed -e 's/ 1$/.old/; s/ 2$//')
+for kernel in ${reverse_sorted_kernels}; do
   # The GRUB_DISABLE_SUBMENU option used to be different than others since it 
   # mentioned in the documentation that has to be set to 'y' instead of 'true' 
   # enable it. This caused a lot of confusion to users that set the option to 
@@ -221,8 +227,6 @@ while [ "x$kernels" != "x" ] ; do
   hurd_entry "$kernel" advanced
   hurd_entry "$kernel" recovery
-  kernels=`echo $kernels | tr ' ' '\n' | fgrep -vx "$kernel" | tr '\n' ' '`
 # If at least one kernel was found, then we need to

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