diff --git a/completions/cppcheck b/completions/cppcheck
index 70b92e76823..2d9b0b7cf94 100644
--- a/completions/cppcheck
+++ b/completions/cppcheck
@@ -81,7 +81,7 @@ _cppcheck()
         COMPREPLY=( $( compgen -W '$( _parse_help "$1" )' -- "$cur" ) )
         [[ $COMPREPLY == *= ]] && compopt -o nospace
     else
-        _filedir @([cht]pp|[cht]xx|cc|[ch]++|[ch])
+        _filedir '@([cht]pp|[cht]xx|cc|[ch]++|[ch])'
     fi
 } &&
 complete -F _cppcheck cppcheck
diff --git a/completions/installpkg b/completions/installpkg
index cdaf816c3c2..400e217e163 100644
--- a/completions/installpkg
+++ b/completions/installpkg
@@ -26,7 +26,7 @@ _installpkg()
         return 0
     fi
 
-    _filedir "t[bglx]z"
+    _filedir 't[bglx]z'
 } && complete -F _installpkg installpkg
 
 # ex: ts=4 sw=4 et filetype=sh
diff --git a/completions/k3b b/completions/k3b
index 9c03642f6e4..6dc96f0f7fa 100644
--- a/completions/k3b
+++ b/completions/k3b
@@ -23,7 +23,7 @@ _k3b()
             return 0
             ;;
         --cdimage|--image)
-            _filedir @(cue|iso|toc)
+            _filedir '@(cue|iso|toc)'
             return 0
             ;;
         --dvdimage)
diff --git a/completions/sqlite3 b/completions/sqlite3
index e97c2e9e266..c5bfcb6d2ce 100644
--- a/completions/sqlite3
+++ b/completions/sqlite3
@@ -22,7 +22,7 @@ _sqlite3()
         return 0
     fi
 
-    _filedir $dbexts
+    _filedir "$dbexts"
 } &&
 complete -F _sqlite3 sqlite3
 
diff --git a/completions/tar b/completions/tar
index 374e0692723..8d867d00be3 100644
--- a/completions/tar
+++ b/completions/tar
@@ -27,7 +27,7 @@ _tar()
                     *[jy]*) ext='t@(?(ar.)bz?(2)|b2)' ;;
                     *J*)    ext='t?(ar.)xz'           ;;
                 esac
-                _filedir $ext
+                _filedir "$ext"
             else
                 _filedir
             fi
diff --git a/completions/upgradepkg b/completions/upgradepkg
index f9fa23ab0ff..5fc4f4dd915 100644
--- a/completions/upgradepkg
+++ b/completions/upgradepkg
@@ -23,7 +23,7 @@ _upgradepkg()
         return
     fi
 
-    _filedir "t[bglx]z"
+    _filedir 't[bglx]z'
 } && complete -F _upgradepkg upgradepkg
 
 # ex: ts=4 sw=4 et filetype=sh