diff --git a/completions-core/apache2ctl.bash b/completions-core/apache2ctl.bash
index 08077888c99..17e1f6024df 100644
--- a/completions-core/apache2ctl.bash
+++ b/completions-core/apache2ctl.bash
@@ -6,10 +6,9 @@ _comp_cmd_apache2ctl()
     _comp_initialize -- "$@" || return
 
     local APWORDS
-    APWORDS=$("$1" 2>&1 >/dev/null | _comp_awk 'NR<2 { print $3; exit }' |
-        tr "|" " ")
+    APWORDS=$("$1" 2>&1 >/dev/null | _comp_awk 'NR < 2 { print $3; exit }')
 
-    _comp_compgen -- -W "$APWORDS"
+    _comp_compgen_split -F $' \t\n|' -- "$APWORDS"
 } &&
     complete -F _comp_cmd_apache2ctl apache2ctl
 
diff --git a/completions-core/bk.bash b/completions-core/bk.bash
index 5a9ec1be8a1..e08b32fde5d 100644
--- a/completions-core/bk.bash
+++ b/completions-core/bk.bash
@@ -7,7 +7,7 @@ _comp_cmd_bk()
     _comp_initialize -- "$@" || return
 
     local BKCMDS=$(bk help topics 2>/dev/null |
-        _comp_awk '/^  bk/ { print $2 }' | xargs printf '%s ')
+        _comp_awk '/^  bk/ { print $2 }')
 
     _comp_compgen -- -W "$BKCMDS"
     _comp_compgen -a filedir
diff --git a/completions-core/gcc.bash b/completions-core/gcc.bash
index ed5bc9b3297..6ca8934c72c 100644
--- a/completions-core/gcc.bash
+++ b/completions-core/gcc.bash
@@ -12,7 +12,7 @@ _comp_cmd_gcc()
             local cc=$("$1" -print-prog-name=cc1 2>/dev/null)
             [[ $cc ]] || return
             _comp_compgen_split -- "$("$cc" --help 2>/dev/null | tr '\t' ' ' |
-                command sed -e '/^  *-/!d' -e 's/ *-\([^][ <>]*\).*/-\1/')"
+                command sed -n 's/^ \{1,\}\(-[^][ <>]*\).*/\1/p')"
             [[ ${COMPREPLY-} == *= ]] && compopt -o nospace
         else
             _comp_compgen_filedir
diff --git a/completions-core/tshark.bash b/completions-core/tshark.bash
index 04ed4260a9e..edea1f3341d 100644
--- a/completions-core/tshark.bash
+++ b/completions-core/tshark.bash
@@ -22,11 +22,10 @@ _comp_cmd_tshark()
             if [[ $cur == *:* ]]; then
                 _comp_compgen -c "${cur#*:}" filedir
             else
-                [[ -v _comp_cmd_tshark__prefs ]] ||
-                    _comp_cmd_tshark__prefs=$("$1" -G defaultprefs 2>/dev/null | command sed -ne 's/^#\{0,1\}\([a-z0-9_.-]\{1,\}:\).*/\1/p' |
-                        tr '\n' ' ')
-                : ${prefix:=}
-                _comp_compgen -P "$prefix" -- -W "$_comp_cmd_tshark__prefs"
+                [[ -v _comp_cmd_tshark__mut_prefs ]] ||
+                    _comp_cmd_tshark__mut_prefs=$("$1" -G defaultprefs 2>/dev/null |
+                        command sed -ne 's/^#\{0,1\}\([a-z0-9_.-]\{1,\}:\).*/\1/p')
+                _comp_compgen -P "$prefix" -- -W "$_comp_cmd_tshark__mut_prefs"
                 [[ ${COMPREPLY-} == *: ]] && compopt -o nospace
             fi
             return
@@ -71,10 +70,10 @@ _comp_cmd_tshark()
             return
             ;;
         -*O)
-            [[ -v _comp_cmd_tshark__protocols ]] ||
-                _comp_cmd_tshark__protocols=$("$1" -G protocols 2>/dev/null |
-                    cut -f 3 | tr '\n' ' ')
-            _comp_delimited , -W "$_comp_cmd_tshark__protocols"
+            [[ -v _comp_cmd_tshark__mut_protocols ]] ||
+                _comp_cmd_tshark__mut_protocols=$("$1" -G protocols 2>/dev/null |
+                    cut -f 3)
+            _comp_delimited , -W "$_comp_cmd_tshark__mut_protocols"
             return
             ;;
         -*T)
diff --git a/completions-core/update-rc.d.bash b/completions-core/update-rc.d.bash
index a5040d44724..4c5f6ba82a7 100644
--- a/completions-core/update-rc.d.bash
+++ b/completions-core/update-rc.d.bash
@@ -17,8 +17,9 @@ _comp_cmd_update_rc_d()
     options=(-f -n)
 
     if [[ $cword -eq 1 || $prev == -* ]]; then
+        local IFS='|'
         _comp_compgen -- -W '"${options[@]}" ${services[@]+"${services[@]}"}' \
-            -X '$(tr " " "|" <<<${words[@]})'
+            -X "@(${words[*]}))"
     elif ((${#services[@]})) && [[ $prev == ?($(tr " " "|" <<<"${services[*]}")) ]]; then
         _comp_compgen -- -W 'remove defaults start stop'
     elif [[ $prev == defaults && $cur == [0-9] ]]; then
diff --git a/completions-fallback/modules.bash b/completions-fallback/modules.bash
index 7e7003468d8..4f7a7164ed6 100644
--- a/completions-fallback/modules.bash
+++ b/completions-fallback/modules.bash
@@ -53,8 +53,8 @@ _comp_cmd_module()
         # First parameter on line -- we expect it to be a mode selection
 
         local options
-        options=$(module help 2>&1 | command grep -E '^[[:space:]]*\+' |
-            _comp_awk '{print $2}' | command sed -e 's/|/ /g' | sort)
+        options=$(module help 2>&1 | _comp_awk '/^[[:space:]]*\+/ {
+            $0 = $2; gsub(/\|/, " "); print }' | sort)
 
         _comp_compgen -- -W "$options"
 
diff --git a/test/t/test_tshark.py b/test/t/test_tshark.py
index d44e62d48c7..d7799323340 100644
--- a/test/t/test_tshark.py
+++ b/test/t/test_tshark.py
@@ -1,7 +1,6 @@
 import pytest
 
 
-@pytest.mark.bashcomp(ignore_env=r"^\+_comp_cmd_tshark__pr(ef|otocol)s=")
 class TestTshark:
     @pytest.mark.complete("tshark -", require_cmd=True)
     def test_1(self, completion):