diff --git a/bin/cron/osh-remove-empty-folders.sh b/bin/cron/osh-remove-empty-folders.sh
index b6007a0..61aa12b 100755
--- a/bin/cron/osh-remove-empty-folders.sh
+++ b/bin/cron/osh-remove-empty-folders.sh
@@ -20,16 +20,23 @@ script_init osh-remove-empty-folders config_optional check_secure_lax
 
 # first, we list all the directories to get a count
 _log "Counting the number of directories before the cleanup..."
-nbdirs_before=$(find /home/ -mindepth 3 -maxdepth 3 -type d -regextype egrep -regex '^/home/[^/]+/ttyrec/[0-9.]+$' -print | wc -l)
+# shellcheck disable=SC2086
+nbdirs_before=$(find $FIND_EGREP_POSITIONAL_BEFORE /home/ -mindepth 3 -maxdepth 3 -type d \
+    $FIND_EGREP_POSITIONAL_AFTER '^/home/[^/]+/ttyrec/[0-9.]+$' -print | wc -l)
 
 _log "We have $nbdirs_before directories, removing empty ones..."
 # then we pass them all through rmdir, it'll just fail on non-empty ones.
 # this is (way) faster than trying to be smart and listing each and every directory's contents first.
-find /home/ -mindepth 3 -maxdepth 3 -type d -mtime +$MTIME_DAYS -regextype egrep -regex '^/home/[^/]+/ttyrec/[0-9.]+$' -print0 | xargs -r0 rmdir -- 2>/dev/null
+# shellcheck disable=SC2086
+find $FIND_EGREP_POSITIONAL_BEFORE /home/ -mindepth 3 -maxdepth 3 -type d \
+    -mtime +$MTIME_DAYS $FIND_EGREP_POSITIONAL_AFTER -regex '^/home/[^/]+/ttyrec/[0-9.]+$' -print0 | \
+    xargs -r0 rmdir -- 2>/dev/null
 
 # finally, see how many directories remain
 _log "Counting the number of directories after the cleanup..."
-nbdirs_after=$(find /home/ -mindepth 3 -maxdepth 3 -type d -regextype egrep -regex '^/home/[^/]+/ttyrec/[0-9.]+$' -print | wc -l)
+# shellcheck disable=SC2086
+nbdirs_after=$(find $FIND_EGREP_POSITIONAL_BEFORE /home/ -mindepth 3 -maxdepth 3 -type d \
+    $FIND_EGREP_POSITIONAL_AFTER -regex '^/home/[^/]+/ttyrec/[0-9.]+$' -print | wc -l)
 
 _log "Finally deleted $((nbdirs_before - nbdirs_after)) directories in this run"
 
diff --git a/bin/cron/osh-rotate-ttyrec.sh b/bin/cron/osh-rotate-ttyrec.sh
index 9e9c3d8..00d02cf 100755
--- a/bin/cron/osh-rotate-ttyrec.sh
+++ b/bin/cron/osh-rotate-ttyrec.sh
@@ -32,7 +32,7 @@ if [ "$1" = "--big-only" ]; then
     fi
 else
     _log "Rotating all ttyrec files..."
-    if pkill --signal USR1 ttyrec; then
+    if pkill -USR1 ttyrec; then
         _log "Rotation done"
     else
         _log "No ttyrec files to rotate"
diff --git a/lib/shell/functions.inc b/lib/shell/functions.inc
index 03630e0..e92bff1 100644
--- a/lib/shell/functions.inc
+++ b/lib/shell/functions.inc
@@ -30,11 +30,6 @@ if [ -z "$LINUX_DISTRO" ] || [ -z "$DISTRO_VERSION" ]; then
     fi
 fi
 
-# special case while bookworm is not yet released
-if [ "$DISTRO_VERSION" = "bookworm/sid" ]; then
-    DISTRO_VERSION=12
-fi
-
 LINUX_DISTRO=$(echo "$LINUX_DISTRO" | tr '[:upper:]' '[:lower:]' | tr -d ' ')
 # shellcheck disable=SC2034
 DISTRO_VERSION_MAJOR=$(echo "$DISTRO_VERSION" | grep -Eo '^[0-9]+' || true)
@@ -92,6 +87,16 @@ if [ ! -e "$CRON_DIR" ]; then
     CRON_DIR=/etc/cron.d
 fi
 
+# set proper `find' options for egrep-style regex matching
+# shellcheck disable=SC2034
+if [ "$OS_FAMILY" = FreeBSD ]; then
+    FIND_EGREP_POSITIONAL_BEFORE='-E'
+    FIND_EGREP_POSITIONAL_AFTER=''
+else
+    FIND_EGREP_POSITIONAL_BEFORE=''
+    FIND_EGREP_POSITIONAL_AFTER='-regextype egrep'
+fi
+
 action_doing()
 {
     printf '\r*** %b\n' "$*"